Backport of puppi changes from 80X to 76X

[violatingcp]

These are changes to the puppi code in 80X. This includes :

1. Addition of PuppiPhoton (with all fixes from 80X)
2. Addition of Puppi Jet corrector flags
3. Code to build puppi MET collections for MiniAOD Puppi MET

This does not include :

1. 80X tune of puppi (with loosened forward particle cuts)
2. Updaed MiniAOD MET reconstruction code for Puppi

The 2 updates below will come with a bigger pull request that also includes the addition of the MET Uncertainties code.

[cmsbuild]

A new Pull Request was created by @violatingcp (Philip Harris) for CMSSW_7_6_X.

It involves the following packages:

CommonTools/PileupAlgos
JetMETCorrections/Configuration
PhysicsTools/PatAlgos

@cmsbuild, @cvuosalo, @slava77, @davidlange6 can you please review it and eventually sign? Thanks.
@rappoccio, @imarches, @ahinzmann, @acaudron, @mmarionncern, @jdolen, @nhanvtran, @schoef, @ferencek, @gpetruc, @mariadalfonso, @pvmulder, @TaiSakuma this is something you requested to watch as well.
@slava77, @Degano, @smuzaffar you are the release manager for this.

cms-bot commands are list here #13028

[slava77]

@cmsbuild please test
IIUC, this changes miniAOD
I'm not aware of a solid plan so far to allow updates that change miniAOD in 76X.

[cmsbuild]

The tests are being triggered in jenkins.
https://cmssdt.cern.ch/jenkins/job/ib-any-integration/12228/console

[mariadalfonso]

@slava77 .
These files here are only partial backport of the 80X. These alone would not change the miniAOD since are not inserted in any sequence (miniOAD production, miniAOD-->miniAOD). But better to have in the release than flying around.

For now the 76X backport (met side) include all these in a separate private recipe
CMSSW_7_6_X...cms-met:metTool76X
that I'm trying to slim.

[cmsbuild]

+1
Tested at: 5106c33
https://cmssdt.cern.ch/SDT/jenkins-artifacts/pull-request-integration/PR-13975/12228/summary.html

[cmsbuild]

Comparison is ready
https://cmssdt.cern.ch/SDT/jenkins-artifacts/pull-request-integration/PR-13975/12228/summary.html

[slava77]

@cmsbuild please test
something happened to the original comparisons (none show up in #13975 (comment))

[cmsbuild]

The tests are being triggered in jenkins.
https://cmssdt.cern.ch/jenkins/job/ib-any-integration/12446/console

[cmsbuild]

+1
Tested at: 5106c33
https://cmssdt.cern.ch/SDT/jenkins-artifacts/pull-request-integration/PR-13975/12446/summary.html

[cmsbuild]

Comparison is ready
https://cmssdt.cern.ch/SDT/jenkins-artifacts/pull-request-integration/PR-13975/12446/summary.html

[slava77]

+1

for #13975 5106c33

• changes are in line with the description: backported only parts of what is in 80X -- mostly added with MET PAT tool update + update of MET significance #13115 -- that do not modify miniAOD)
• jenkins tests pass and comparisons with baseline show no differences