Use Floating Action Button for buttons on map fragments

Features
#1

1. What is the general goal of the feature?
Currently, multiple options are displayed using AppCompatImageButtons on map fragment. Shifting to using Floating Action Button can provide a fresher look to the Geowidgets. I am attaching a wireframe and a screenshot of the app.

Screenshot at 2020-06-18 22-36-14
Screenshot at 2020-06-18 22-36-14733×734 107 KB

screenshot_mapfragment_fab
screenshot_mapfragment_fab540×1170 44.6 KB

I used mini and normal Floating Action Buttons, and also changed the placement of the buttons a little bit.

Your views and feedback on this are welcome. :slight_smile:

#2

This is what we started talking about here as well https://github.com/getodk/collect/issues/3202