UI/API: Astra DB destination connector - flatten metadata toggle (#522)

Author: Paul-Cornell

snippets/destination_connectors/astradb_rest_create.mdx

@@ -13,7 +13,8 @@ curl --request 'POST' --location \
         "api_endpoint": "<api-endpoint>",
         "collection_name": "<collection-name>",
         "keyspace": "<keyspace>",
-        "batch_size": <batch-size>
+        "batch_size": <batch-size>,
+        "flatten_metadata": "<true|false>"
     }
 }'
 ```

snippets/destination_connectors/astradb_sdk.mdx

@@ -20,7 +20,8 @@ with UnstructuredClient(api_key_auth=os.getenv("UNSTRUCTURED_API_KEY")) as clien
                     api_endpoint="<api-endpoint>",
                     collection_name="<collection-name>",
                     keyspace="<keyspace>",
-                    batch_size=<batch-size>
+                    batch_size=<batch-size>,
+                    flatten_metadata=<True|False>
                 )
             )
         )

snippets/general-shared-text/astradb-api-placeholders.mdx

@@ -4,3 +4,4 @@
 - `<collection-name>` (_required_) - The name of the collection in the namespace.
 - `<keyspace>` - The name of the keyspace in the collection. The default is `default_keyspace` if not otherwise specified.
 - `<batch-size>` - The maximum number of records to send per batch. The default is `20` if not otherwise specified.
+- `flatten_metadata` - Set to `true` to flatten the metadata into each record. Specifically, when flattened, the metadata key values are brought to the top level of the element, and the `metadata` key itself is removed. By default, the metadata is not flattened (`false`).

snippets/general-shared-text/astradb-platform.mdx

@@ -4,5 +4,8 @@ Fill in the following fields:
 - **Collection Name** (_required_): The name of the collection in the namespace.
 - **Keyspace** (_required_): The name of the keyspace in the collection.
 - **Batch Size**: The maximum number of records per batch. The default is `20` if not otherwise specified.
+- **Flatten Metadata**: Check this box to flatten the metadata into each record. 
+  Specifically, when flattened, the metadata key values are 
+  brought to the top level of the element, and the `metadata` key itself is removed. By default, the metadata is not flattened.
 - **API Endpoint** (_required_): The database's associated API endpoint.
 - **Token** (_required_): The application token for the database.