Add embed-in-json transformer docs

Adds documentation for the embed-in-json transformer.

Signed-off-by: Daniel Mangum <[email protected]>

docs/data-routing/3-transformers/8-embed-in-json.md

@@ -0,0 +1,51 @@
+---
+title: embed-in-json
+---
+
+|   |   |
+|---|:---:|
+|__Latest Version__| `v1.0.0` |
+|__Input Content Type__| Any |
+|__Output Content Type__| `application/json` |
+
+The `embed-in-json` transformer embeds data as a UTF-8 JSON string value for the
+specifed string key in a new JSON object.
+
+:::info Tip
+When dealing with binary data, it may be helpful to use the [`base64`
+transformer](/data-routing/transformers/base64) to encode the data as text prior
+to embedding. The [`json-patch`
+transformer](/data-routing/transformers/json-patch) may be used to modify the
+JSON object after embedding.
+:::
+
+
+### Parameters
+
+|Parameter|Type|Description|Required|
+|---|---|---|:---:|
+|`key`|`string`| The key that input data should be assigned to. |✅|
+
+### Example Usage
+
+```yaml
+    transformer:
+      type: embed-in-json
+      version: v1
+      parameters:
+        key: original
+```
+
+### Example Input
+
+```
+hello, world!
+```
+
+### Example Output
+
+```json
+{
+  "original": "hello, world!"
+}
+```