Add a new Attribute for static methods. [OnHotReload]

[Clancey]

This allows us to hook into the HotReload for a specific type. This will allow us to register a class or reset defaults when a class is HotReloaded

[mattleibow]

I think I like this. Simple and sweet, but powerful. Also better than the unit as well as only accessed via reflection meaning it can get linked out.

[jsuarezruiz]

I like it!.

Just a small change to fix the build:
ReflectionMethodComparer.Equals(MethodInfo g1, MethodInfo g2) in HotReloadExtensions.cs must be ReflectionMethodComparer.Equals(MethodInfo? g1, MethodInfo? g2)
(Nullability checks)