Rita - Self report 3

[ritacatuxo]

In this sprint I did the the tests for the user management, modificating the user-service and auth-service accordingly for them. I also created the openAPI documentation for user service, and updated the documentation.

Issues:
#120
#127
#145

Pull requests:
#157
#161
#155

[pglez82]

Important: this self-report should be modified including also links not only to issues but to specific pull requests or commits that clearly show your contributions in the repository.