Add location accuracy

[iandolge]

Add altitude and accuracy figures to the LatLon class

This changes the LatLon class to include extra attributes but maintains that this class is comparable to a tuple of (lat, lng). See core/tests/test_types.py for the contract. Each platform that supports location has been modified to populate these values.

Makes accuracy information available for macOS, iOS, Android, and Linux(GTK)

Fixes #3112

PR Checklist:

• I will abide by the BeeWare Code of Conduct
• I have read and have followed the CONTRIBUTING.md file
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[iandolge]

@freakboy3742 I think I'm settled on the implementation but I still need to go through and update tests beyond the core tests and check things out. I know the naming remains awkward and the altitude now exists in two spots, any feedback would be welcome.

[freakboy3742]

I think the main issue here is that the data types we've got here aren't what we need (and that's historical - not something you've introduced). We've separated LatLng from altitude - and that complicates everything we're doing, and ends up with us trying to cram altitude into a LatLng sized hole.

I'm wondering if the solution here is to:

1. Rename the LatLng structure to something like GeoPosition that includes accuracy and altitude components
2. Modify the on_change handler to return position, location and altitude
3. Formally deprecate the location and altitude arguments to on_change (and raise warnings when an on_change handler is set by inspecting the handler that is provided

Does that makes sense?

[iandolge]

I think that makes sense! I'll make another round of updates this weekend.