Add group role mapping

[DavidFair]

Description:

• Adds assign group to an existing project
• Adds the steps to add a user to a project

Testing

• Create a group in OpenStack using admin creds: https://docs.openstack.org/python-openstackclient/pike/cli/command-objects/group.html
• Assign a group to an existing project (e.g. scratch project)
• Add a user to that group, e.g. another developer, they should see your project

Special Notes:

---

Submitter:

Have you (where applicable):

• Added unit tests?
• Checked the latest commit runs on Dev?
• Updated the example config file(s) and README?

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Reviewer

Does this PR:

• Place non-StackStorm code into the lib directory?
• Have unit tests for the action/sensor and lib layers?
• Have clear and obvious action parameter names and descriptions?

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 98.21%. Comparing base (61479cf) to head (200b4f9).
Report is 1 commits behind head on main.

Additional details and impacted files

@@            Coverage Diff             @@
##             main     #306      +/-   ##
==========================================
+ Coverage   98.19%   98.21%   +0.01%     
==========================================
  Files         128      128              
  Lines        4718     4768      +50     
  Branches      251      251              
==========================================
+ Hits         4633     4683      +50     
  Misses         76       76              
  Partials        9        9              

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