feat(ElementInjector): implement ElementInjector

Initial implementation of ElementInjector.

Works:
1. The creation of proto element injector trees
2. Bindings
3. The instantiation of element injectors
4. The instantiation of directives
5. Visibility: Parent and Ancestor
6. Delegation to application injectors
7. Error handling

Missing features:
1. Handling components.
2. Setting "special" properties (e.g., Element, View).
3. Cycle detection
`@FIELD` are not used for now - and they probably never will be used but this PR is lacking some at different places.

The current plan is to have `@FIELD('_appInjector:Injector')` -> `_appInjector:Injector', easy to migrate with a regexp