feat(android): added docs

[finger563]

Description

• Added docs for helping setup the android build. Tested and works with existing app without changes required :)

Motivation and Context

Closes #3

How has this been tested?

Building and running on my Pixel 5

Screenshots (if appropriate, e.g. schematic, board, console logs, lab pictures):

Types of changes

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to not work as expected)
• Documentation Update
• Software change

Checklist:

• My change requires a change to the documentation.
• I have added / updated the documentation related to this change via either README or WIKI

Software

• I have added tests to cover my changes.
• All new and existing tests passed.
• My code follows the code style of this project.