[Bug]: `overseerr-k8s` is missing key rotations

[adhityaravi]

Description

The overseerr charm is missing the API key key rotation logic. Initially this was decided because it shares this key with no one. But this is not reason enough to not have it rotate it's key. Unlike Plex, this API key is something that can indeed bet set, so it should infact be rotated to stick to the charmarr pattern.

Steps to Reproduce

1. Look at the charmcraft.yaml of the overseerr-k8s charm
2. No key rotation related config or action
3. Neither does the source code have the logic for this

Expected Behavior

overseerr-k8s follows the charmarr story of having secure auto rotating keys

Actual Behavior

Environment

overseerr-k8s: latest/edge

Logs

Additional Context

No response