Active plugins (#4553)

Task/Issue URL: https://app.asana.com/0/488551667048375/1207335546470303/f

### Description
This PR adds active plugin points, ie. plugin points that are automatically guarded by remote feature flags.

See [this](https://app.asana.com/0/1202552961248957/1207322408444916/f) for more context

### Steps to test this PR
_Test Main Process_
- [x] build and install from #4554
- [x] filter logcat by `UserOfThePluginPoint | Aitor`
- [x] launch the app
- [x] verify `Main`, `Baz`, `Bar`, `Second Main` plugins print in that order and `In Process main`
- [x] Enable AppTP
- [x] verify `Main`, `Baz`, `Bar`, `Second Main` plugins print in that order and `In Process vpn`
- [x] Disable Baz plugin
```
    "pluginPointMyPlugin": {
      "exceptions": [],
      "state": "enabled",
      "hash": "1",
      "features": {
        "pluginBazActivePlugin": {
          "state": "disabled"
        }
      }
    }
```
- [x] use fire button to update remote config
- [x] verify `Main`, `Bar`, `Second Main` plugins print in that order and `In Process main`
- [x] Disable and re-enable AppTP
- [x] verify `Main`, `Bar`, `Second Main` plugins print in that order and `In Process vpn`
- [x] Disable Bar plugin
```
    "pluginPointMyPlugin": {
      "exceptions": [],
      "state": "enabled",
      "hash": "2",
      "features": {
        "pluginBarActivePlugin": {
          "state": "disabled"
        }
      }
    }
```
- [x] verify `Main`, `Second Main` plugins print in that order and `In Process main`
- [x] Disable and re-enable AppTP
- [x] verify `Main`, `Second Main` plugins print in that order and `In Process vpn`
- [x] Disable plugin point
```
    "pluginPointMyPlugin": {
      "exceptions": [],
      "state": "disabled",
      "hash": "3",
      "features": {
      }
    }
```
- [x] verify no plugin prints any message
- [x] Disable and re-enable AppTP
- [x] verify no plugin prints any message
- [x] re-enable plugin point and all plugins
```
    "pluginPointMyPlugin": {
      "hash": "5",
      "exceptions": [],
      "state": "enabled",
      "features": {
        "pluginBazActivePlugin": {
          "state": "enabled"
        },
        "pluginBarActivePlugin": {
          "state": "enabled"
        }
      }
    }
```
- [x] verify `Main`, `Baz`, `Bar`, `Second Main` plugins print in that order and `In Process main`
- [x] Disable and re-enable AppTP
- [x] verify `Main`, `Baz`, `Bar`, `Second Main` plugins print in that order and `In Process vpn`
- [x] disable all plugins individually
```
    "pluginPointMyPlugin": {
      "exceptions": [],
      "state": "enabled",
      "hash": "6",
      "features": {
        "pluginBazActivePlugin": {
          "state": "disabled"
        },
        "pluginBarActivePlugin": {
          "state": "disabled"
        },
        "pluginFooActivePlugin": {
          "state": "disabled"
        },
        "pluginMainActivePlugin": {
          "state": "disabled"
        },
        "pluginSecondMainActivePlugin": {
          "state": "disabled"
        }
      }
    }
```
- [x] verify no plugin prints any message
- [x] Disable and re-enable AppTP
- [x] verify no plugin prints any message
- [x] re-enable all individually
- [x] verify `Main`, `Baz`, `Bar`, `Second Main` plugins print in that order and `In Process main`
- [x] Disable and re-enable AppTP
- [x] verify `Main`, `Baz`, `Bar`, `Second Main` plugins print in that order and `In Process vpn`

anvil/anvil-annotations/src/main/java/com/duckduckgo/anvil/annotations/ContributesActivePlugin.kt

@@ -0,0 +1,63 @@
+/*
+ * Copyright (c) 2024 DuckDuckGo
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package com.duckduckgo.anvil.annotations
+
+import kotlin.reflect.KClass
+
+/**
+ * Anvil annotation to contribute plugins into an Active Plugin Point.
+ * Active plugins are also guarded by remote feature flags
+ *
+ * This annotation is the counterpart of [ContributesActivePluginPoint]
+ *
+ * Usage:
+ * ```kotlin
+ * @ContributesActivePlugin(SomeDaggerScope::class)
+ * class MyPluginImpl : MyPlugin {
+ *
+ * }
+ *
+ * interface MyPlugin : ActivePluginPoint.ActivePlugin {...}
+ * ```
+ */
+@Target(AnnotationTarget.CLASS)
+@Retention(AnnotationRetention.RUNTIME)
+annotation class ContributesActivePlugin(
+    /** The scope in which to include this contributed PluginPoint */
+    val scope: KClass<*>,
+
+    /**
+     * This is the type of the plugin the annotated class is extending from
+     * This is a required member to help the code generation.
+     */
+    val boundType: KClass<*>,
+
+    /**
+     * The default value of remote feature flag.
+     * Default is true (ie. enabled)
+     */
+    val defaultActiveValue: Boolean = true,
+
+    /**
+     * The priority for the plugin.
+     * Lower priority values mean the associated plugin comes first in the list of plugins.
+     *
+     * This is equivalent to the [PriorityKey] annotation we use with [ContributesMultibinding] for normal plugins.
+     * The [ContributesActivePlugin] coalesce both
+     */
+    val priority: Int = 0,
+)

anvil/anvil-annotations/src/main/java/com/duckduckgo/anvil/annotations/ContributesActivePluginPoint.kt

@@ -0,0 +1,56 @@
+/*
+ * Copyright (c) 2024 DuckDuckGo
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package com.duckduckgo.anvil.annotations
+
+import kotlin.reflect.KClass
+
+/**
+ * Anvil annotation to generate plugin points that are guarded by a remote feature flag.
+ *
+ * Active plugins need to extend from [ActivePluginPoint.ActivePlugin]
+ *
+ * Usage:
+ * ```kotlin
+ * @ContributesActivePluginPoint(SomeDaggerScope::class)
+ * interface MyPlugin : ActivePluginPoint.ActivePlugin {
+ *
+ * }
+ * ```
+ */
+@Target(AnnotationTarget.CLASS)
+@Retention(AnnotationRetention.RUNTIME)
+annotation class ContributesActivePluginPoint(
+    /** The scope in which to include this contributed PluginPoint */
+    val scope: KClass<*>,
+
+    /**
+     * The type that the plugin point will be bound to. This is useful when the plugin interfaces are defined in
+     * modules where we don't want or can't generate code, eg. API gradle modules.
+     *
+     * usage:
+     * ```kotlin
+     * @ContributesActivePluginPoint(
+     *   scope = AppScope::class,
+     *   boundType: MyPlugin::class
+     * )
+     * interface MyPluginPoint : MyPlugin
+     *
+     * interface MyPlugin : ActivePluginPoint.ActivePlugin {...}
+     * ```
+     */
+    val boundType: KClass<*> = Unit::class,
+)