Add methods to components to simplify replacing children

# Problem to solve

Would be useful to expose simplified ways to replace components within the component tree.


However it is not immediately obvious how these APIs would work wrt some aspects.

# Proposal

I originally wrote [this PR](https://github.com/flame-engine/flame/pull/2303) as a proposal but there was a lot of discussion on the PR about how exactly they should work.

Someone would need to dig into the discussion and figure out the best approach. The actual PR code might or might not be useful at all depending on the chosen requirements.