More flexible order of mobjects in the scene.

[Morkunas]

Description of proposed feature

It would be amazing, if we were able to specify more flexible order of mobjects in the scene.
For example: if mob1 was behind mob2, mob2 was behind mob3 and mob3 was behind mob1.
Currently, one mobject will always be behind all others.

Here is a visual example.
I think, the best we can do right now is something like this. Note how pink circle is in the back.

Ideally, it would be possible to achieve something like this. Note that each circle covers exactly one other circle:

Thank you!

How can the new feature be used?

Mostly more flexibility in the scene where we have non trivial dependencies between mobjects.

Additional comments

[k4pran]

Are you using the cairo (default) renderer or opengl? There is a PR #2235 open currently to begin implementing something like this for opengl. We have also been having discussions on discord whether this idea could also work for cairo. I agree though that we should be able to have more control over order

[Morkunas]

Hey! Thanks for the response! Currently I am using Cairo! But this could be a good reason to move to opengl!