Mobile Support

[ManevilleF]

@alice-i-cecile asked me to add Android and iOS basics to this project from my cross-platform template

Added:

• assets/res classic mobile resource assets folder, with the icon
• Basic Android configuration in Cargo.toml following cargo-apk manifest
• a basic Xcode project in the apple folder with a Makefile inspired by this bevy example

Changed:

• The project is now both a lib and a bin

I still need to test everything before setting this to ready

Notes:

• I didn't change the bevy version which is still 0.6
• I didn't touch the wasm part, even though I don't think it should work as the index.html requires bevy_game.js when the project name is bevy_github_ci_template

[alice-i-cecile]

Ping @mockersf for review.

[ManevilleF]

The iOS part is working:

• I didn't add the whole app icon setup which adds lots of files and configurations
• i fixed the app bundle
• I added audio support, required because of bevy_audio

[mockersf]

thinking back on this PR, I think it would make more sense to have a separate template for mobile