Implement hecs Query for DynamicBundle

[cart]

This would provide useful shorthand in "function systems" when there are a lot of components. Something like:

#[derive(Bundle)]
struct MyBundle {
  a: ComponentA,
  b: ComponentB
}

fn some_system(component_group: Bundle<MyBundle>) {
  println!("a: {:?}", component_group.a);
  println!("b: {:?}", component_group.b);
}

Ideally it could be used alongside normal queries like (&MyComponent, Bundle<MyBundle>)

[Moxinilian]

Implemented in #798