Merged in NRRPLT-8215-collab-2 (pull request #123)

[NRRPLT-8215] Support to authentication via Ebrains Collab v2

* [NRRPLT-8215] 477 response message
* [NRRPLT-8215] added separate config for frontend auth clientID and URL
* [NRRPLT-8215] mock userid in identity request
* [NRRPLT-8215] cleanup identity endpoints location
* [NRRPLT-8215] replace client ids in tests
* [NRRPLT-8215] add a comment about usersList

Approved-by: Sandro Weber
Approved-by: Vahid Zolfaghari