Migrate HitTripletGeneratorFromPairAndLayers classes to SeedingLayerSetsHits
Migrate CombinedHitTripletGenerator to SeedingLayerSetsHits
Migrate CombinedMultiHitGenerator, MultiHitGeneratorFromPairAndLayers, MultiHitGeneratorFromChi2
Migrate configuration: TobTecLayerPairs_cfi
Migrate configuration: PixelLessLayerPairs_cfi
Migrate configuration: PixelLessLayerPairs4PixelLessTracking_cfi
Migrate configuration: PixelLayerTriplets_cfi
Migrate configuration: PixelLayerPairs_cfi
Migrate configuration: PixelAndStripLayerPairs_cfi
Migrate bunch of configuration files without any knock-on effects
Migrate conversion configuration files
Migrate configuration: thirdStep_cff
Migrate configuration: secondStep_cff
Migrate EgammaHLTRegionalPixelSeedGeneratorProducers
Migrate QuadrupletSeedMerger

In QuadrupletSeedMerger SeedingLayerSets are used only to iterate over
layer-quadruplets. Therefore SeedingLayersEDProducer would mean
unnecessary work by creating the TTRHs. Therefore I decided to just
deliver the SeedingLayerSetsBuilder PSet to QuadrupletSeedMerger, and
construct SeedingLayerSetsBuilder in the constructor.
Remove SeedingLayerESProducer as obsolete
Add edm::ConsumesCollector parameter to SeedFilter constructor

Will need to deliver edm::ConsumesCollector to OrderedHitsGenerator in
SeedFilter (to be added in a later commit).

As a knock-on effect, move SeedFilter construction from beginRun() to
constructor in ElectronSeedProducer. Also, use std::unique_ptr for
SeedFilter.
Add edm::ConsumesCollector to OrderedHitsGenerator constructors

Will be needed to deliver edm::ConsumesCollector to
- CombinedHitPairGenerator
- CombinedMultiHitGenerator
- CombinedHitTripletGenerator
- CombinedHitPairGeneratorForPhotonConversion
- CombinedHitQuadrupletGeneratorForPhotonConversion

Following concrete classes inherit from OrderedHitsGenerator
- BeamHaloPairGenerator
- GenericPairGenerator
- GenericTripletGenerator
- CombinedHitPairGenerator
- CombinedMultiHitGenerator
- CombinedHitTripletGenerator
- CombinedHitPairGeneratorForPhotonConversion
- CombinedHitQuadrupletGeneratorForPhotonConversion

Knock-on effects:

Pass ConsumesCollector to OrderedHitsFactory
- TSGSmart

+ move construction of OrderedHitsGenerator to constructor
- TSGFromL1Muon (from beginRun)
- PixelTrackReconstruction (from beginRun)
- HitTripletProducer (from init)
- CtfSpecialSeedGenerator (from beginRun)
- PhotonConversionTrajectorySeedProducerFromSingleLegAlgo (from init)
- ConversionSeedGenerators/src/PhotonConversionTrajectorySeedProducerFromQuadrupletsAlgo (from init)

+ move construction of SeedGeneratorFromRegionHits to constructor
- TSGFromOrderedHits
- EgammaHLTRegionalPixelSeedGeneratorProducers

+ move construction of SeedComparitor and SeedCreator to constructor
- SeedGeneratorFromRegionHitsEDProducer
Migrate SeedingLayerSetsHits consumers to getByToken
Construct HitExtractors in SeedingLayerSetsBuilder constructor

Needed for edm::ConsumesCollector (in later commit).