backport of quark and gluons Py8EGun in CMSSW_10_2_X

[vberta]

PR description:

Added a feature to the Py8EGun: now the gun can use also quark or gluons. This feature was already present in the Py8PtGun, but not in the EGun.
This feature is required for the MC production for the training of DeeoCore Algorithm in forward region. see this jira ticked for details: [(https://its.cern.ch/jira/browse/PDMVRELVALS-65#add-comment)].

if this PR is a backport please specify the original PR:

This is the original PR on master. Because the modification is a single file, I did it by hand reimplementing the features (copy-paste of the modified line instead using rebase/cherry pick of the commit).
#28658

[cmsbuild]

A new Pull Request was created by @vberta for CMSSW_10_2_X.

It involves the following packages:

GeneratorInterface/Pythia8Interface

@SiewYan, @efeyazgan, @mkirsano, @cmsbuild, @agrohsje, @alberto-sanchez, @qliphy can you please review it and eventually sign? Thanks.
@alberto-sanchez, @agrohsje, @mkirsano this is something you requested to watch as well.
@davidlange6, @silviodonato, @fabiocos you are the release manager for this.

cms-bot commands are listed here

[qliphy]

please test

[cmsbuild]

The tests are being triggered in jenkins.
https://cmssdt.cern.ch/jenkins/job/ib-run-pr-tests/4218/console Started: 2020/01/14 05:15

[cmsbuild]

+1
Tested at: 47e3a7b
https://cmssdt.cern.ch/SDT/jenkins-artifacts/pull-request-integration/PR-b87716/4218/summary.html
CMSSW: CMSSW_10_2_X_2020-01-13-2300
SCRAM_ARCH: slc6_amd64_gcc700

[cmsbuild]

Comparison job queued.

[cmsbuild]

Comparison is ready
https://cmssdt.cern.ch/SDT/jenkins-artifacts/pull-request-integration/PR-b87716/4218/summary.html

Comparison Summary:

• No significant changes to the logs found
• Reco comparison results: 4 differences found in the comparisons
• DQMHistoTests: Total files compared: 31
• DQMHistoTests: Total histograms compared: 3007491
• DQMHistoTests: Total failures: 3
• DQMHistoTests: Total nulls: 0
• DQMHistoTests: Total successes: 3007298
• DQMHistoTests: Total skipped: 190
• DQMHistoTests: Total Missing objects: 0
• DQMHistoSizes: Histogram memory added: 0.0 KiB( 30 files compared)
• Checked 129 log files, 14 edm output root files, 31 DQM output files

[qliphy]

+1

[cmsbuild]

This pull request is fully signed and it will be integrated in one of the next CMSSW_10_2_X IBs (tests are also fine) and once validation in the development release cycle CMSSW_11_1_X is complete. This pull request will now be reviewed by the release team before it's merged. @davidlange6, @silviodonato, @fabiocos (and backports should be raised in the release meeting by the corresponding L2)

[silviodonato]

@vberta please update the title of this PR to something more clear.

[silviodonato]

+1