* Acquire token for NoSQL account prior to running tests.
* Change client id to user assigned managed identity.
* Change to use managed identity. Add token variables for gremlin and
tables.
* Add RBAC details to test README.
* Add token for SQL readonly database. Skip resource token tests when RBAC
enabled.
* Use hardcoded account name for sql readonly.
* Use specific tag for sql readonly.
* Remove comment.
