feat(core): add support for @Property and @Event decorators

Example:

@Directive({selector: 'my-selector'})
class MyDirective {
  @Property() prop;
  @Property('el-prop') prop2;
  @Event() event;
  @Event('el-event') event2;
}

Closes #3992

modules_dart/transform/lib/src/transform/template_compiler/reflection/reflection_capabilities.dart

@@ -20,6 +20,8 @@ class NullReflectionCapabilities implements ReflectionCapabilities {
 
   List annotations(typeOrFunc) => _notImplemented('annotations');
 
+  Map propMetadata(typeOrFunc) => _notImplemented('propMetadata');
+
   GetterFn getter(String name) => _nullGetter;
 
   SetterFn setter(String name) => _nullSetter;