"fake grafana.net authentication"

[Dieterbe]

currently we still talk to grafana.net for a few things. i get often confronted with:

1. authenticating worldping plugin, though you can use changeme and auth as master org
2. anything that talks to tsdb-gw authenticates with a gnet key (carbon-relay-ng and fakemetrics)

for the 2nd case, i often want to test with a key, but my data then ends up being stored as whatever orgid i have assigned in gnet. so i can't see the data through the raintank datasource that the WP plugin creates.

so maybe we should have a small "fake grafana.net" in a container that can serve as authentication service, and will authenticate as a user/org that we can choose?