Add HeavyIon-isolation producer to pp photons - backport of #12152

[ttrk]

backport of #12152

This PR adds the HI-style isolation to the pp photon sequences. Heavy Ions needs this information during the pp reference run in order to do proper comparisons to PbPb results, where this information will be used for photon ID.

It will add two instances of the HIPhotonIsolation ValueMap, one for "std" photons and another for GED photons to the RECO and AOD event content for pp events.
This is urgent, as the pp reference run is approaching soon.

@richard-cms
@yenjie

[cmsbuild]

A new Pull Request was created by @ttrk for CMSSW_7_5_X.

Add HeavyIon-isolation producer to pp photons - backport of #12152

It involves the following packages:

RecoEgamma/Configuration
RecoEgamma/EgammaPhotonProducers
RecoHI/HiEgammaAlgos

@cmsbuild, @cvuosalo, @slava77 can you please review it and eventually sign? Thanks.
@Sam-Harper, @jazzitup, @lgray, @richard-cms, @yenjie, @kurtejung, @istaslis, @mandrenguyen, @dgulhan, @yetkinyilmaz this is something you requested to watch as well.
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@Degano you are the release manager for this.
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[slava77]

#12153 (comment)

[ttrk]

this PR is superseded by #12185