Annotation type should extend Comment type

For the need of integrating ARender annotations into the CommentService, we want to make Annotation type extend Comment type.

As it, every ARender annotations will be a comment and will benefit of all comment's features inside Nuxeo.

This is a breaking change compared to 10.2, because Annotation are currently linked to a document + blob using ids stored in its metadata. Whereas Comment is linked to a document or a comment with help of RelationService.

CommentService should be called from AnnotationService to deal with annotations.

Move all annotations related classes to comment module as annotations are just a sub type of comment.