Add new configuration document for connection datadog (#100)

docs/reference/config-files/connection/datadog.md

@@ -0,0 +1,37 @@
+---
+title: datadog
+sidebar_label: datadog
+---
+
+# datadog
+
+The `datadog` connection can be used to access Datadog resources.
+
+```hcl
+connection "datadog" "my_datadog_connection" {
+  api_key = "b1cf234................."
+  app_key = "1a2345bc..................."
+  api_url = "https://api.adoghq.com/"
+}
+```
+
+## Arguments
+
+| Name      | Type   | Required? | Description     |
+| --------- | ------ | --------- | --------------- |
+| `api_key` | String | Optional  | API key         |
+| `app_key` | String | Optional  | Application key |
+| `api_url` | String | Optional  | API URL         |
+
+All arguments are optional, and a `datadog` connection with no arguments will behave the same as the [default connection](#default-connection).
+
+## Default Connection
+
+The `datadog` connection type includes an implicit, default connection (`connection.datadog.default`) that will be configured using the environment variables `DD_CLIENT_API_KEY`, and `DD_CLIENT_APP_KEY`.
+
+```hcl
+connection "datadog" "my_datadog_connection" {
+  api_key = env("DD_CLIENT_API_KEY")
+  app_key = env("DD_CLIENT_APP_KEY")
+}
+```