feat: max_age is set during auth request to limit user session

[JorTurFer]

Description

Currently, the cli is relaying only on the user session duration on the identity server side. This isn't aligned with the fact of limiting the session by the cli because create an scenario where I need to login because the cli considers the session closed but the identity server doesn't, so it's a "not useful" security measure and it requires that constant browser starts just to get a token without any user interaction.

This PR also extends the session duration to 12h

relates to #https://github.com/stackitcloud/terraform-provider-stackit/issues/719

Checklist

• [x] Issue was linked above
• [x] Code format was applied: make fmt
• [x] Examples were added / adjusted (see e.g. here)
• [x] Docs are up-to-date: make generate-docs (will be checked by CI)
• [x] Unit tests got implemented or updated
• [x] Unit tests are passing: make test (will be checked by CI)
• [x] No linter issues: make lint (will be checked by CI)