[8.0] IAM2CS: ForceNickname, fix duplicate accounts for users

[andresailer]

BEGINRELEASENOTES

*ConfigurationSystem
CHANGE: VOMS2CSAgent: if a nickname is set, this nickname will always be used and no new accounts are going to be created if a DN changes or a user is in multiple VOs
NEW: VOMS2CSAgent: New option "ForceNickname", if this option is enabled no dirac user is created if no nickname attribute is set for a user
CHANGE: IAMService: use logger and return errors for users so that the VOMS2CSAgent can notify admins about issues

ENDRELEASENOTES

[DIRACGridBot]

Sweep summary

Sweep ran in https://github.com/DIRACGrid/DIRAC/actions/runs/10902080612

Failed:

• integration
  cherry-pick 3fc58a8 into integration failed
  check merge conflicts on a local copy of this repository

  git fetch upstream
  git checkout upstream/integration -b cherry-pick-2-3fc58a8e9-integration
  git cherry-pick -x -m 1 3fc58a8e9
  # Fix the conflicts
  git cherry-pick --continue
  git commit --amend -m 'sweep: #7784 IAM2CS: ForceNickname, fix duplicate accounts for users' --author='Andre Sailer <[email protected]>'
  git push -u origin cherry-pick-2-3fc58a8e9-integration
  
  # If you have the GitHub CLI installed the PR can be made with
  gh pr create \
       --label 'sweep:from rel-v8r0' \
       --base integration \
       --repo DIRACGrid/DIRAC \
       --title '[sweep:integration] IAM2CS: ForceNickname, fix duplicate accounts for users' \
       --body 'Sweep #7784 `IAM2CS: ForceNickname, fix duplicate accounts for users` to `integration`.
  
  Adding original author @andresailer as watcher.
  
  BEGINRELEASENOTES
  
  *ConfigurationSystem
  CHANGE: VOMS2CSAgent: if a nickname is set, this nickname will always be used and no new accounts are going to be created if a DN changes or a user is in multiple VOs
  NEW: VOMS2CSAgent: New option "ForceNickname", if this option is enabled no dirac user is created if no nickname attribute is set for a user
  CHANGE: IAMService: use logger and return errors for users so that the VOMS2CSAgent can notify admins about issues
  
  ENDRELEASENOTES
  Closes #7795'