Add missing APIs to Service API

[SBriere]

Is your feature request related to a problem? Please describe.
Some features are not available yet to the Service API.

Describe the solution you'd like
Implement the following APIs:

- [ ] /users/access - GET: allow service to query roles not related to a specific project / site and not for the OpenTeraService only -> Will be accessed with the token

• /users/access - Implement POST / DELETE to allow service to add users to specific roles
• /roles - Implement GET / POST / DELETE to allow service to manage their own roles
• /projects - Implement POST / DELETE to allow services to manage projects (don't forget to associate service to that project if new!)
• /usergroups - Implement GET / POST / DELETE to allow services to manage user groups
• Make roles available in tokens