Refactor geolocation to prepare actor for uplifting

I am working towards moving the geolocation simulating functionality up to m-c, so that it will already be on-device in the future.

In that vein, I've extracted several actors from the general purpose `dbg-simulator-actors` into `dbg-geolocation-actors` and `dbg-geolocation-ui-actors`.

`dbg-geolocation-actor` is what I would want to get on-device. `dbg-geolocation-ui-actors` is very much dependent on the simulator's UI flow for controlling the geolocation settings, and since that may change significantly with the App Manager, I will leave this here in the simulator add-on for now.

I will likely extend `dbg-geolocation-actor` before moving it on device (as part of issue #804 and perhaps others).