Feature: Use backend as a proxy instead

[koalalorenzo]

Since the Grafana API have CORS, we need to use the container as a proxy to perform queries for data sources, metrics labels and other data that might be useful for autocomplete.

Currently the setup is designed for The LEGO Group and uses the internal API, though we could make it easier to fork if we switch to using the container/service running not just to provide the front-end but also to authenticate and forward API calls to Grafana.

[koalalorenzo]

We added an env variable to change this.

We need to add documentation about it.

[koalalorenzo]

done in #20