Our goal of this CR is to automate the OAuth token flows using a central IDP (OIDC) so that a user does not need to individually and manually pass the OAuth flow.

In order to make it as easy as possible for new users we need to come up with a good, detailed plan. It involves at least:

* Univention
* OIDC setup Begin of the insertion(Keycloak I guess)End of the insertion
* Nextcloud
* Begin of the deletion for lettingEnd of the deletion Nextcloud core accept/verify and store those sessions Begin of the insertionon incoming API requestsEnd of the insertion
* Begin of the deletion for ourEnd of the deletion Nextcloud app Begin of the insertion
* End of the insertion to accept/verify (ideally handled by core) Begin of the insertionincoming API requests for API endpoints that are provided by the app
* uses suchEnd of the insertion Begin of the deletion and use thoseEnd of the deletion sessions for outgoing requests Begin of the insertionto OpenProjectEnd of the insertion
* OpenProject
* Begin of the insertionAllowingEnd of the insertion Begin of the deletion for allowingEnd of the deletion OpenProject to be configured to use that special type of setup
* Begin of the insertionAccept/verifyEnd of the insertion Begin of the deletion accept/verifyEnd of the deletion these tokens Begin of the insertionon incoming API requestsEnd of the insertion
* Begin of the insertionStoreEnd of the insertion Begin of the deletion storeEnd of the deletion tokens in the session for a user
* Begin of the insertionMake the the file storageEnd of the insertion Begin of the deletion make our StorageEnd of the deletion connection use those tokens when emitting requests to Nextcloud
* Take special care of the background jobs (they currently use a Nextcloud app password as there is no user session)

> This plan is still pretty rough. This is an integration topic with high complexity but definitely worth the effort. I recommend to work with proofs of concept in the beginning. It also requires that all three involved parties are working closely together.