[FEATURE] Convert menus into standalone scenes, loaded additively, instead of as prefabs.

[japtar10101]

Is your feature request related to a problem? Please describe.

Menus as prefabs introduces layout problems that are difficult to preview and test functionality of. Separating them out as standalone scenes would go a long way in keeping the layouts consistent.

Describe the solution you'd like

Convert menu prefabs into actual scenes. Remove the original set of prefabs to greatly reduce the number of assets in the project/package.

Tasklist

• Script signals to send to the menus on how it should animate upon loading.
• Figure out how to make the background of menus play nicely with other menus.
• Figure out how to make managed vs. unmanaged menus work nicely with each other.

Describe alternatives you've considered

Using prefabs, as it currently is right now.