Update to bevy v0.9

[66OJ66]

Updates bevy_atmosphere to use Bevy v0.9

Change Summary:

• Add #[derive(Resource)] for all resources
• Temporarily use https://github.com/BlackPhlox/bevy_flycam until merged into https://github.com/sburris0/bevy_flycam
• Replace spawn_bundle() with spawn() and simplify insert() logic (I've conformed to Option 2 as mentioned here https://bevyengine.org/learn/book/migration-guides/0.8-0.9/#accept-bundles-for-insert-and-remove-deprecate-insert-remove-bundle)
• Minor fixes for the Timer in the cycle example

[JonahPlusPlus]

Thanks, but I have started work on this (see #30). I want to make some extra changes before releasing, and maybe add a new feature, like night skies or a new sky model.

[JonahPlusPlus]

Also, I am going to change bevy_flycam to my own bevy_spectator (a bit cleaner to use and I'll be giving some community members permissions to make updates if I'm not available).

[66OJ66]

Ah okay, fair enough! Closing this PR