Review accessibility of app

[barbeau]

Is your feature request related to a problem? Please describe.
There are accessibility guidelines for Android here:
https://developer.android.com/guide/topics/ui/accessibility/apps

Describe the solution you'd like
We need to review these and see if MUSER complies. We may need to increase text size and control size to greater than the guidelines here for our target audience.

We should especially look at the contentDescription for TalkBack to see if that is currently implemented for blind and low vision users.

Describe alternatives you've considered
N/A

[barbeau]

Separate issue opened for contentDescriptions here - #121.

This issue will focus on general UI control size and font size.