[Android] Allow selecting between GPS provider and fused location

**Is your feature request related to a problem? Please describe.**
Fused location might be inaccurate in some scenarios, and I've seen it giving a location less accurate than the GPS provider although there's a GPS signal available.

**Describe the solution you'd like**
Since this is only related to android, I thought a configuration string can be added like the icon to allow the code to use GPS provider instead of fused location.

**Describe alternatives you've considered**
I might be able to filter out locations that have low accuracy, but I rather avoid it.

**Additional context**
The implementation itself is not that complicated and I was able to do it on a fork I'm working on, but I'm mainly interested to know if this is something that should be here or kept in a fork.
The main use case that I want the locations in the background is for recording user hikes and travels, and I want the recording to be as accurate as possible in order for later or to allow the user to update OSM with this information.

No file or test is identified in the issue. Start by locating the Android background-location implementation and its existing configuration options, then verify how a provider choice could be exposed; the work is done when users can select GPS or fused location and background updates use that choice.

Written by the indexing model from the issue text.