iLCSoft v02-03-04 release on EL/Alma9

[tmadlener]

BEGINRELEASENOTES

• Create a first release on EL9 / Alma9
  • Using gcc13, python3.11.9
  • Switching to c++20
• Add Dockerfile to build CVMFS installation container
• Fix a few minor build issues in some packages

ENDRELEASENOTES

• package versions to release notes
• squash a few commits for a cleaner history to make rebase and merge make more sense
• Test build

[tmadlener]

I have switched to picking up Qt5 and xrootd from the underlying LCG_106 stack, because I could not get a successful build for Qt5 and roots builtin_xrootd didn't work for me either.

I managed to get release-base to build without any manual intervention this way, but for release-ilcsoft there are still a few manual edits necessary to get it to build. As far as I can see the following PRs need to get merged first in order to fully build the stack without manual intervention:

• Move assignments outside of if statement PandoraPFA/PandoraSDK#18 (this one can be avoided by building Pandora with c++17 instead of c++20)
• Fix the dictionary generation on several platforms lcfiplus/LCFIPlus#72

Some other PRs would be nice to have, but are, I think, not critical

• Use recommended way to set the c++ standard via cmake PandoraPFA/PandoraMonitoring#11
• Use the recommended way to set the c++ standard via cmake PandoraPFA/LCContent#23