Make user sessions last longer so people dont have to log in as often

[olevski]

Currently user sessions are really short and users have to log in every 24 hours. Even though the cookies from gitlab and/or keycloak last way longer. So this is not even a true login because as soon as you click the "login" button then you get your renku session refreshed and you are not asked for any credentials at gitlab or keycloak.

[leafty]

The session lifecycle can be configured by admins:
https://github.com/SwissDataScienceCenter/renku/blob/d13b9c6100150b2d10615db3f2bb63d3e7f211f4/helm-chart/renku/values.yaml#L1274-L1285