Expand README.md to include install guide

[isabellabrookes]

Noteworthy:

• Node
• JDK 11 or lower
• Xcode
• iphone 11
• Android studio
• pixel 2
• (npm script lists specific emulators)
• Cocoapods

[adilanchian]

This has been PUSHED. The README is currently in release-1.0 and song-comments

Any sort of changes on this would be GREATLY appreciated :)