Implement From<DynamicBundle> and From<DynamicBundleClone> for EntityBuilder{Clone}

[ten3roberts]

This feature would greatly improve the workflow of kickstarting a builder when a function requires one, and the user knows they only need one bundle.

This is used in the project I am making and in hecs-hierarchy to construct entities in tree and so on.

The issue can be circumvented by first creating a builder, and then passing it in to the CreateInfo, however, it would be easier if it could be given a headstart of a bundle, by MyBundle {..}.into() which returns a builder.

One of the usage of builders is as type erased bundles for storage in structs and templates for spawning entities by name later.

[Ralith]

Sounds like a reasonable and straightforward API extension to me!