Add foreman_user module

[ogajduse]

This module allows managing Foreman users. I've tested the module manually and everything should work except the following.

• the second run of the module with the same arguments using auth_source: INTERNAL will fail with 422
• can not change the password once is set

I haven't found support for auth_source_externals, auth_source_internals and auth_sources in Nailgun. This is something that needs to be done to provide full functionality of the foreman_user module. There is also missing support for current_password parameter while using PUT.

I haven't put any effort into creating any tests for this module yet. I will come back to it later.

[mdellweg]

Just a first glance, but this looks very promising.

In case you have not yet seen it, take a look at:
https://github.com/theforeman/foreman-ansible-modules#how-to-test-modules-in-this-repository

[ogajduse]

@mdellweg thanks for the first check
Added tests for this module. I won't be adding the fixtures until the following Nailgun issues will be solved:

• Nailgun is missing ability to change password for the existing user SatelliteQE/nailgun#591
• Nailgun can not access auth_source_externals, auth_source_internals and auth_sources endpoints SatelliteQE/nailgun#594

[ogajduse]

This PR is obsoleted by #296.

[mdellweg]

Thank you for the efford. #296 has been merged.