[v8r0] Fix MySQL Optimizer and don't start JobAgent for integration tests

[chaen]

This reduces the execution time by 8mn. The server installation is installing the JobAgent as a "normal" agent, which of course does not make sense

2022-10-12 16:03:12 UTC WorkloadManagement/JobAgent/WorkloadManagement/JobAgent [140224957937472] INFO: MatcherTime = 0.04 (s)
2022-10-12 16:03:12 UTC WorkloadManagement/JobAgent/WorkloadManagement/JobAgent [140224957937472] NOTICE: Failed to get jobs Error requesting job
2022-10-12 16:11:12 UTC WorkloadManagement/JobAgent/WorkloadManagement/JobAgent [140224957937472] NOTICE: ----------------------------------------
2022-10-12 16:11:12 UTC WorkloadManagement/JobAgent/WorkloadManagement/JobAgent [140224957937472] NOTICE: Agent module WorkloadManagement/JobAgent run summary
2022-10-12 16:11:12 UTC WorkloadManagement/JobAgent/WorkloadManagement/JobAgent [140224957937472] NOTICE:  Executed 1 times previously
2022-10-12 16:11:12 UTC WorkloadManagement/JobAgent/WorkloadManagement/JobAgent [140224957937472] NOTICE:  Cycle took 480.13 seconds
2022-10-12 16:11:12 UTC WorkloadManagement/JobAgent/WorkloadManagement/JobAgent [140224957937472] NOTICE:  Average execution time: 480.13 seconds
2022-10-12 16:11:12 UTC WorkloadManagement/JobAgent [140224882960128] DEBUG: Refreshing configuration...
2022-10-12 16:11:12 UTC WorkloadManagement/JobAgent/WorkloadManagement/JobAgent [140224957937472] NOTICE:  Polling time: 120 seconds
2022-10-12 16:11:12 UTC WorkloadManagement/JobAgent/WorkloadManagement/JobAgent [140224957937472] NOTICE:  Average execution/polling time: 400.11%
2022-10-12 16:11:12 UTC WorkloadManagement/JobAgent/WorkloadManagement/JobAgent [140224957937472] NOTICE:  Cycle was successful
2022-10-12 16:11:12 UTC WorkloadManagement/JobAgent/WorkloadManagement/JobAgent [140224957937472] NOTICE: ----------------------------------------
2022-10-12 16:11:12 UTC WorkloadManagement/JobAgent [140224957937472] INFO: No more agent modules to execute. Exiting

Also, it fixes the MySQL tracer I've introduced. I have absolutely no idea how I got it working last time...

BEGINRELEASENOTES
*Test
FIX: server installation do not install JobAgent

*Core
FIX: MySQL tracer bugs

ENDRELEASENOTES

[fstagni]

Well JobAgent is a "real" agent but it is not something to start on server side.

[DIRACGridBot]

Sweep summary

Sweep ran in https://github.com/DIRACGrid/DIRAC/actions/runs/3240422603

Failed:

• integration
  cherry-pick 262ef12 into integration failed
  check merge conflicts on a local copy of this repository

  git fetch upstream
  git checkout upstream/integration -b cherry-pick-2-262ef120a-integration
  git cherry-pick -x -m 1 262ef120a
  # Fix the conflicts
  git cherry-pick --continue
  git commit --amend -m 'sweep: #6411 Fix MySQL Optimizer and don'"'"'t start JobAgent for integration tests' --author='chaen <christophe.haen@cern.ch>'
  git push -u origin cherry-pick-2-262ef120a-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] Fix MySQL Optimizer and don'"'"'t start JobAgent for integration tests' \
       --body 'Sweep #6411 `Fix MySQL Optimizer and don'"'"'t start JobAgent for integration tests` to `integration`.
  
  Adding original author @chaen as watcher.
  
  BEGINRELEASENOTES
  *Test
  FIX: server installation do not install JobAgent
  
  *Core
  FIX: MySQL tracer bugs
  
  ENDRELEASENOTES
  Closes #6413'