feat: global openmeteo class

Usage example:
```
@OptIn(Response.UnitTimeStepValues.GlueUnitTimeStepValues::class)
fun main() {
    val om = OpenMeteo("Trieste", "it").getOrThrow()
    val forecast = om.forecast {
        daily = Forecast.Daily {
            listOf(temperature2mMin, temperature2mMax)
        }
        temperatureUnit = TemperatureUnit.Fahrenheit
        timezone = Timezone.auto
    }.getOrThrow()
    Forecast.Daily.run {
        forecast.daily.getValue(temperature2mMax).run {
            println("# $temperature2mMax ($unit)")
            values.forEach{ (t, v) -> println("> $t | $v") }
        }
    }
}
```

src/main/kotlin/com/openmeteo/api/OpenMeteo.kt

@@ -0,0 +1,111 @@
+package com.openmeteo.api
+
+import com.openmeteo.api.common.query.City
+import com.openmeteo.api.common.time.Date
+import java.net.URL
+
+/**
+ * A global class to ease latitude/longitude and geocoding api calls.
+ *
+ * Usage example:
+ * ```
+ * @OptIn(Response.UnitTimeStepValues.GlueUnitTimeStepValues::class)
+ * fun main() {
+ *     val om = OpenMeteo("Trieste", "it").getOrThrow()
+ *     val forecast = om.forecast {
+ *         daily = Forecast.Daily {
+ *             listOf(temperature2mMin, temperature2mMax)
+ *         }
+ *         temperatureUnit = TemperatureUnit.Fahrenheit
+ *         timezone = Timezone.auto
+ *     }.getOrThrow()
+ *     Forecast.Daily.run {
+ *         forecast.daily.getValue(temperature2mMax).run {
+ *             println("# $temperature2mMax ($unit)")
+ *             values.forEach{ (t, v) -> println("> $t | $v") }
+ *         }
+ *     }
+ * }
+ * ```
+ */
+open class OpenMeteo(
+    var latitude: Float,
+    var longitude: Float,
+    var apikey: String? = null,
+) {
+
+    constructor(city: City, apikey: String? = null)
+        : this(city.latitude, city.longitude, apikey)
+
+    companion object {
+
+        operator fun invoke(id: Int, language: String? = null, apikey: String? = null) =
+            GeocodingGet(id) {
+                this.language = language
+                this.apikey = apikey
+            }.map { OpenMeteo(it.latitude, it.longitude, apikey) }
+
+        /**
+         * Search a location with the Geocoding API.
+         * Fetches one element and uses its coordinates by default.
+         * Note that language is only used in the query and it is **not** stored
+         * (e.g. search "Roma" instead of "Rome", with "it" as language).
+         */
+        operator fun invoke(location: String, language: String? = null, apikey: String? = null) =
+            GeocodingSearch(location) {
+                this.language = language
+                this.count = 1
+                this.apikey = apikey
+            }.mapCatching { (results) ->
+                if (results.isEmpty()) throw Error("No results!")
+                OpenMeteo(results[0].latitude, results[0].longitude, apikey)
+            }
+
+    }
+
+    inline fun airQuality(
+        context: URL = AirQuality.context,
+        query: AirQuality.Query.() -> Unit,
+    ) = AirQuality(latitude, longitude, apikey, context, query)
+
+    inline fun climateChange(
+        models: String,
+        startDate: Date,
+        endDate: Date,
+        context: URL = ClimateChange.context,
+        query: ClimateChange.Query.() -> Unit,
+    ) = ClimateChange(latitude, longitude, models, startDate, endDate, apikey, context, query)
+
+    inline fun elevation(
+        context: URL = Elevation.context,
+        query: Elevation.Query.() -> Unit,
+    ) = Elevation(latitude, longitude, apikey, context, query)
+
+    inline fun ensemble(
+        context: URL = Ensemble.context,
+        query: Ensemble.Query.() -> Unit,
+    ) = Ensemble(latitude, longitude, apikey, context, query)
+
+    inline fun flood(
+        context: URL = Flood.context,
+        query: Flood.Query.() -> Unit,
+    ) = Flood(latitude, longitude, apikey, context, query)
+
+    inline fun forecast(
+        context: URL = Forecast.context,
+        query: Forecast.Query.() -> Unit,
+    ) = Forecast(latitude, longitude, apikey, context, query)
+
+    inline fun historical(
+        startDate: Date,
+        endDate: Date,
+        context: URL = Historical.context,
+        query: Historical.Query.() -> Unit,
+    ) = Historical(latitude, longitude, startDate, endDate, apikey, context, query)
+
+    inline fun marine(
+        context: URL = Marine.context,
+        query: Marine.Query.() -> Unit,
+    ) = Marine(latitude, longitude, apikey, context, query)
+
+}