port CRAB code to new python 3.13

[belforte]

see dmwm/WMCore#12208 (comment)

[belforte]

@aspiringmind-code @sinonkt
this is up for pick... please get a sense of what it is involved, then one of you can volunteer.
I have no idea how it may impact our build scripts e.g. How closely we need to synchronize with changes in WMCore, etc. etc.

[belforte]

while you are at this, make sure that code in ServerUtilities which is shared with CRABClient stays compatible with python2.7 and be aware that CRABClient always runs with the python version set by the CMSSW Release specified by the user. Check with Shahzad if there are plans for upgrading python there.

Of course moving code which is not used by Client out of ServerUtilities in some proper (new) file in CRABServer/src/python/CRABUtils can only help, that ServerUtilities file is way too long now.

[belforte]

Additional complication:

• scripts in the schedulers use code from GH repository but run with /usr/bin/python3
• JobWrapper (CMSRunAnalysis.py, cmscp.py) run with the python3 from /cvmfs/cms.cern.ch/COMP which is under WMCore control

So if you can have code which works with both current py3.8 and new py3.13, should be all simple, otherwise a lot of care will be needed and transition will take longer due to the need of multiple backward-compatible steps.

[belforte]

On the good side, HTCondor V2 API's should be python-version-independent. Of course to be verified.