Support for module hot reloading

[KaruroChori]

I have been working on a proof of concept project to add hot-lib-reloader-rs in bevy alongside kayak_ui. However I cannot put together a reasonable implementation to force the full re-rendering of a widget once a new version of it is compiled and exposed.
The rendering functions for widgets already spawned cannot be trivially replaced.

Having hot reload support in a library like this would be extremely beneficial, allowing for a simple and faster workflow.

[SET001]

I was experimenting with [hot-lib-reloader-rs](https://github.com/rksm/hot-lib-reloader-rs) but whatever I try I was getting seg fault after reloading *( I can drop a repo with an example implementation if it helps.