Limit permissions and include missing certificates in security tests [20170]

[tempate]

In this version, we have:

• Generated a security certificate per participant to avoid sharing certificates.
• Restricted the permissions to the strictly necessary.
• Replaced the tests' README files with comments in the compose files (the current standard).

In the process, we discovered a Fast-DDS issue:

• https://github.com/eProsima/Fast-DDS/pull/4188

[codecov[bot]]

Codecov Report

All modified and coverable lines are covered by tests :white_check_mark:

Project coverage is 30.41%. Comparing base (bda15bc) to head (6dd4946). Report is 16 commits behind head on main.

Additional details and impacted files

@@           Coverage Diff           @@
##             main     #418   +/-   ##
=======================================
  Coverage   30.41%   30.41%           
=======================================
  Files          16       16           
  Lines         559      559           
  Branches      297      297           
=======================================
  Hits          170      170           
  Misses        202      202           
  Partials      187      187           

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