Split shared prefs based on usage

[kylecorry31]

Currently the shared prefs contain both cache and settings, but should only contain settings.

Some ideas:

• [ ] Create a second data store for caching (default remains settings)
• [ ] Create a data store for each source (pedometer, GPS, altimeter, etc)
• [ ] Create two new stores: cache (sensor & device specific) and other (not sure what to call it right now - but contains the flags that indicate a user acknowledged a dialog / one time messages)

And then on backup/restore potentially don't back up the sensor/device cache.