Add option to enter static location of the computer

### Problem

Mozilla has closed its location service (https://discourse.mozilla.org/t/retiring-the-mozilla-location-service/128693) that geoclue2 was using. Google location service requires a paid API key. IP based location resolution is unreliable in certain situations, because it depends on many external factors. This creates issues, like automated theme switching based on sunrise/sunset times not working realiably.

### Proposal

For desktop PCs, that usually stay at the same place, this can be solved by creating a /etc/geolocation file with static coordinates (as per `man geoclue`). This could be available as an option in the Settings app, with the possibility to switch from automated location to static location. The required coordinates can be easily obtained with a service like OpenStreetMap.

### Prior Art (Optional)

_No response_