[8.0] Drop CloudCE proxy handling

[sfayer]

Hi,

Now that the pilot wrapper always includes a bundled proxy, we don't need to handle writing one specially in the cloud scripts, so this patch drops all of that functionality. This also fixes a recent v8 bug where CloudCE keeps self.proxy in a different format (string rather than proxy object) to other CEs resulting in a SiteDirector crash.

[Note: Users with a custom cloudinit.template will need to update it to match these changes].

Regards,
Simon

BEGINRELEASENOTES
*Resources
FIX: Drop CloudCE proxy handling
ENDRELEASENOTES

[DIRACGridBot]

Sweep summary

Sweep ran in https://github.com/DIRACGrid/DIRAC/actions/runs/11300362440

Failed:

• integration
  cherry-pick 7e453ce into integration failed
  check merge conflicts on a local copy of this repository

  git fetch upstream
  git checkout upstream/integration -b cherry-pick-2-7e453ce0f-integration
  git cherry-pick -x -m 1 7e453ce0f
  # Fix the conflicts
  git cherry-pick --continue
  git commit --amend -m 'sweep: #7823 Drop CloudCE proxy handling' --author='Simon Fayer <[email protected]>'
  git push -u origin cherry-pick-2-7e453ce0f-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] Drop CloudCE proxy handling' \
       --body 'Sweep #7823 `Drop CloudCE proxy handling` to `integration`.
  
  Adding original author @sfayer as watcher.
  
  BEGINRELEASENOTES
  *Resources
  FIX: Drop CloudCE proxy handling
  ENDRELEASENOTES
  Closes #7828'