[8.0] feat (VOMS2IAM): add options to sync from IAM

[chaen]

Addresses part of https://github.com/DIRACGrid/DIRAC/issues/7416

This does not yet work, because there are still too many bugs in the voms-importer https://github.com/indigo-iam/voms-importer/

Wht this PR does is to add 2 options to the VOMS2CSAgent`:

• CompareWithIAM: when set to true, we will dump the users from IAM, and print a comparison with what VOMS sees
• UseIAM: not query voms-admin anymore, but the IAM endpoint

BEGINRELEASENOTES

• Configuration NEW: VOMS2CSAgent can query IAM

ENDRELEASENOTES

[DIRACGridBot]

Sweep summary

Sweep ran in https://github.com/DIRACGrid/DIRAC/actions/runs/9382608769

Failed:

• integration cherry-pick 97bf94bd5 into integration failed check merge conflicts on a local copy of this repository

  git fetch upstream
  git checkout upstream/integration -b cherry-pick-2-97bf94bd5-integration
  git cherry-pick -x -m 1 97bf94bd5
  # Fix the conflicts
  git cherry-pick --continue
  git commit --amend -m 'sweep: #7612 feat (VOMS2IAM): add options to sync from IAM' --author='Christophe Haen <christophe.haen@cern.ch>'
  git push -u origin cherry-pick-2-97bf94bd5-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] feat (VOMS2IAM): add options to sync from IAM' \
     --body 'Sweep #7612 `feat (VOMS2IAM): add options to sync from IAM` to `integration`.
  
  Adding original author @chaen as watcher.
  
  BEGINRELEASENOTES
  
  * Configuration
  NEW: VOMS2CSAgent can query IAM
  
  ENDRELEASENOTES
  Closes #7647'