Desactivate properly TagService integration in DM when deployed on JCR repository

TagService can not work propertly on a JCR backend because it needs direct access to the repository storage structures.
Since TagService is now bundled by default with DM, it has to be automatically desactivate when deployed on an instance using the JCR backend as default repository.

If needed a flag should be added in the Repository object provided by the RepositoryManager.
Flag should be used to :

• disable Tables creation
• Tag fragment in the default document view
• Tag navigation