Removal of `@Controller`

This PR supersedes #1040.

This PR contains:
- Removal of the `@Controller` annotation,
- No more implicit map dereference (`a.b` always evaluate to `a.b` instead of `a[b]`),
- Removal of the usage of the `probe` directive (which is deprecated),
- Publish NgForm instance on the context
- `@Template` replaces `@Decorator(Directive.TRANSCLUDE_CHILDREN)`

see commit comments for more details