Support OIDC login in studio

[mirkoSekulic]

Ref slack discussion

Tasks

Beta Give feedback

1. Implement OIDC flow in designer #12919
   +0
2. Change current login flow with OIDC #12920
   +0
3. Setup OAuth client for local development automaticly #12921
   +0
4. Setup client for dev #12922
   added-to-sprint +1
5. Setup client for staging #12923
   added-to-sprint +1
6. Setup client for prod #12924
   added-to-sprint +1
   
7. Investigate if it's possible to communicate with libgit2sharp without PAT, or create PAT as part of the login #12925
   added-to-sprint +1
   
8. Create required PAT for deploy app pipeline #12926
   +0
   
9. Adjust tests so they work with oidc login flow #13229
   added-to-sprint +1

[mirkoSekulic]

@framitdavid @nkylstad This is a good candidate for current sprint.

[mlqn]

Closing the epic since all tasks are now solved