add connector traces config to observability docs (#306)

Co-authored-by: Rob Dominguez <[email protected]>

docs/query-plan/traces.mdx

@@ -46,7 +46,9 @@ Every request to your GraphQL API will have a unique `trace-id` associated with
       - `execute`
         - `execute_ndc_query`
           - `Execute Query`
+            - `<Connector spans>`
         - `execute_ndc_mutation`
+          - `<Connector spans>`
 
 | Span name                | Description                                                                                                                                                                                 |
 | ------------------------ | ------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- |
@@ -59,10 +61,26 @@ Every request to your GraphQL API will have a unique `trace-id` associated with
 | `execute_ndc_query`      | The span responsible for executing a single ndc query. This span has an attribute `field` which describes the schema type that was executed.                                                |
 | `Execute Query`          | The span responsible for executing the generated query on the data source.                                                                                                                  |
 | `execute_ndc_mutation`   | The span responsible for executing a single ndc mutation. This span has an attribute `field` which describes the field that was executed.                                                   |
+| `<Connector spans>`      | Optional spans from connectors where the engine sends requests to.                                                                                                                            |
 
 :::info What are spans?
 
 Spans represent the basic unit of work in a distributed system. They describe the operation that an individual component
 of the system is doing, such as the time taken to execute a function or a request.
 
 :::
+
+### Connector spans
+
+Connectors can have internal spans that vary depending on the database or business logic. Those traces are exported
+separately from the connector. You don't need to worry about it If you deploy the connector to DDN cloud. However,
+self-hosted connectors need to configure some variables or you won't see connector traces on DDN console:
+
+- `OTEL_EXPORTER_OTLP_ENDPOINT`: https://gateway.otlp.hasura.io:443
+- `OTEL_EXPORTER_OTLP_HEADERS`: `Authorization=pat <personal-access-token>`
+
+:::info Personal Access Token (PAT)
+
+You can generate a personal access token [here](https://cloud.hasura.io/account-settings/access-tokens).
+
+:::