Implement fillDescriptions in ConversionTrackCandidateProducer

[guitargeek]

PR description:

Implement fillDescriptions in ConversionTrackCandidateProducer and some more modernization of ConversionTrackCandidateProducer and GEDPhotonCoreProducer.

PR validation:

CMSSW compiles, local matrix tests pass.

if this PR is a backport please specify the original PR and why you need to backport that PR:

No backport intended.

[cmsbuild]

+code-checks

Logs: https://cmssdt.cern.ch/SDT/code-checks/cms-sw-PR-32724/20865

• This PR adds an extra 24KB to repository

[cmsbuild]

A new Pull Request was created by @guitargeek (Jonas Rembser) for master.

It involves the following packages:

RecoEgamma/EgammaElectronProducers
RecoEgamma/EgammaPhotonProducers

@perrotta, @jpata, @cmsbuild, @slava77 can you please review it and eventually sign? Thanks.
@Sam-Harper, @jainshilpi, @rovere, @lgray, @sobhatta, @lecriste, @afiqaize, @varuns23, @ram1123 this is something you requested to watch as well.
@silviodonato, @dpiparo, @qliphy you are the release manager for this.

cms-bot commands are listed here

[slava77]

@cmsbuild please test

[cmsbuild]

+1

Summary: https://cmssdt.cern.ch/SDT/jenkins-artifacts/pull-request-integration/PR-e06b0a/12499/summary.html
COMMIT: ce6708c
CMSSW: CMSSW_11_3_X_2021-01-23-1100/slc7_amd64_gcc900
User test area: For local testing, you can use /cvmfs/cms-ci.cern.ch/week0/cms-sw/cmssw/32724/12499/install.sh to create a dev area with all the needed externals and cmssw changes.

Comparison Summary

Summary:

• No significant changes to the logs found
• Reco comparison results: 8 differences found in the comparisons
• DQMHistoTests: Total files compared: 37
• DQMHistoTests: Total histograms compared: 2716961
• DQMHistoTests: Total failures: 12
• DQMHistoTests: Total nulls: 1
• DQMHistoTests: Total successes: 2716926
• DQMHistoTests: Total skipped: 22
• DQMHistoTests: Total Missing objects: 0
• DQMHistoSizes: Histogram memory added: -0.004 KiB( 36 files compared)
• DQMHistoSizes: changed ( 312.0 ): -0.004 KiB MessageLogger/Warnings
• Checked 156 log files, 37 edm output root files, 37 DQM output files

[jpata]

+reconstruction

• technical
• no relevant changes in tests

[cmsbuild]

This pull request is fully signed and it will be integrated in one of the next master IBs (tests are also fine). This pull request will now be reviewed by the release team before it's merged. @silviodonato, @dpiparo, @qliphy (and backports should be raised in the release meeting by the corresponding L2)

[qliphy]

+1