RecHit map and CaloParticle-LayerCluster associator

[lecriste]

PR description:

This PR introduces two products (a std::map and an associator) which can be consumed by several analyzers, removing code duplication. The first replacement is made for the HGVHistoProducerAlgo::fill_generic_cluster_histos method, no changes are expected in the output.

PR validation:

runTheMatrix -l limited

[cmsbuild]

Comparison is ready
https://cmssdt.cern.ch/SDT/jenkins-artifacts/pull-request-integration/PR-c7963d/6507/summary.html

Comparison Summary:

• No significant changes to the logs found
• Reco comparison results: 16 differences found in the comparisons
• DQMHistoTests: Total files compared: 35
• DQMHistoTests: Total histograms compared: 2694466
• DQMHistoTests: Total failures: 42
• DQMHistoTests: Total nulls: 0
• DQMHistoTests: Total successes: 2694375
• DQMHistoTests: Total skipped: 49
• DQMHistoTests: Total Missing objects: 0
• DQMHistoSizes: Histogram memory added: 0.0 KiB( 34 files compared)
• Checked 150 log files, 16 edm output root files, 35 DQM output files

[jfernan2]

+1

[kpedro88]

+upgrade

some improvements (e.g. use of unordered_map) will be addressed in followup PR

[slava77]

+1

for #29844 fc6c8aa

• no changes in reco files since the last signoff (the latest update was in a follow up to my comment though, Thanks!)

[civanch]

+1

[silviodonato]

Do you have any comments? core: @Dr15Jones @makortel @smuzaffar

[makortel]

+1

[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 (and backports should be raised in the release meeting by the corresponding L2)

[silviodonato]

+1