feat: use keycloak to authorize backend calls from the frontend

[ReneSchroederLJ]

Description

• removed API key authorization from frontend
• added keycloak authorization as a second authorization option to the backend
• updated frontend to send keycloak's access token as bearer
• added keycloak to local docker compose deployment
• separated idp config from frontend in values.yaml
• updated admin and migration guide

solves #902, #903

Pre-review checks

Please ensure to do as many of the following checks as possible, before asking for committer review:

• DEPENDENCIES are up-to-date. Dash license tool. Committers can open IP issues for restricted libs.
• Copyright and license header are present on all affected files
• If helm chart has been changed, the chart version has been bumped to either next major, minor or patch level (compared to released chart).

[tom-rm-meyer-ISST]

Feature works great locally.

Tests and helm chart are failing. Proposed changes to fix it.

Further the local deployment can be less ressource intense.

Nevertheless - as always - good work!

[tom-rm-meyer-ISST]

Great work.

Please check comment + the notification dialog results in an api key exception. Likely this dialog has been missed.

[tom-rm-meyer-ISST]

Works great. please bump backend and frontend version

[tom-rm-meyer-ISST]

LGTM, thanks a lot!