[8.0] Preinstalled env pilot options in SiteDirector

[atsareg]

PR to add preinstalledEnv and preinstalledEnvPrefix pilot options in the SiteDirector as defined in DIRACGrid/Pilot#205.

If both PreinstalledEnv and PreinstalledEnvPrefix pilot options are defined, the PreinstalledEnv option is preferred.

BEGINRELEASENOTES

*WorkloadManagement
NEW: SiteDirector - added preinstalledEnv and preinstalledEnvPrefix pilot options

ENDRELEASENOTES

[fstagni]

I think that if one of the 2 options is set, the other should't.

[DIRACGridBot]

Sweep summary

Sweep ran in https://github.com/DIRACGrid/DIRAC/actions/runs/6769080599

Failed:

• integration
  cherry-pick 1af9355 into integration failed
  check merge conflicts on a local copy of this repository

  git fetch upstream
  git checkout upstream/integration -b cherry-pick-2-1af93550b-integration
  git cherry-pick -x -m 1 1af93550b
  # Fix the conflicts
  git cherry-pick --continue
  git commit --amend -m 'sweep: #7266 Preinstalled env pilot options in SiteDirector' --author='Andrei Tsaregorodtsev <[email protected]>'
  git push -u origin cherry-pick-2-1af93550b-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] Preinstalled env pilot options in SiteDirector' \
       --body 'Sweep #7266 `Preinstalled env pilot options in SiteDirector` to `integration`.
  
  Adding original author @atsareg as watcher.
  
  BEGINRELEASENOTES
  
  *WorkloadManagement
  NEW: SiteDirector - added preinstalledEnv and preinstalledEnvPrefix pilot options
  
  ENDRELEASENOTES
  Closes #7270'