Allow components and resources to be defined at run-time

[RiscadoA]

Blocked by #415.

Currently components and resources must be defined as C++ types.
This is a problem if we want to define components or resources in scripts, which are only known at run-time.

To change this we need to make the ECS completely untyped, making component storages store memory blobs, for example.

[RiscadoA]

Making the ECS type-erased could speed up compilation quite a bit and make it way easier to understand - the current code has tons of templates to make up for bad design.

[RiscadoA]

I think it would also be cool to end global registration of components altogether: #378 has become a problem anyway.
This would make #300 impossible, but I think thats not a problem.
We would need to move the name definition to another place - I like cubos.addComponent<Position>("position");.

With that out of the way the only remaining thing for cubinhos to handle would be serialization function definition. We could generalize it to [[cubos::serializable]] instead of [[cubos::component]].

[RiscadoA]

Closed in favor of #462