Upgrade bevy to 0.16

[AS1100K]

This is a tracking issue, the following dependencies haven't upgraded to bevy 0.16

1. bevy_asset_loader Currently release candidate are available
2. bevy_ecs_ldtk Not yet upgraded to bevy 0.16
3. bevy_rapier2d Currently upgraded on master branch

If anyone has time, please feel free to open the PR as it could take me some time to do it.

Ready to Upgrade, No Blockers

[AS1100K]

I have created a branch bevy-0.16, with the upgrade but it comes with quite a lot of bugs. I don't have time now to fix it as it is not that important. I will try it some other day, if anyone else has time feel free to upgrade to 0.16