Incubation:APM Grafana project integration

We have DataDog (potentially other agents too) integration with GitLab projects/environments via api keys - see #27 (closed)

A GitLab user should be able to navigate from a project into a Grafana environment that is limited to viewing data from the project and associated environments.

There is already GitLab OAuth2 login for Grafana. It may be possible to use this directly or modify to associate the OAuth scopes to the individual project.

Any queries run against the data source will be scoped to the individual project.