Authorizers to be moved from graph-commons

[jachro]

As a renku-graph developer, I'd like Authorizers and Authenticators to be moved from the graph-commons module

The problem:
Because the mentioned tooling sits in the graph-commons module, the Datasets graph cannot be used to fetch data needed by the Authorizers. The reason is that graph-commons does not (and should not) depend on the entities-search module so tests for the Authorizers couldn't be written in a sane way.

Acceptance criteria:

• move both Authenticators and Authorizers into a new graph-auth module
• try to find out which of the queries currently back up the auth tooling should/can be using data from the Datasets graph
  • if it would be good to use the Datasets graph, make the new module depending on the entities-search module
  • modify the relevant queries