Migrate HitPairGeneratorFromLayerPair to SeedingLayerSetNew
Migrate CombinedHitPairGenerator to the new SeedingLayerSet
Add new version of LayerTriplets for SeedingLayerSetNew
Migrate HitTripletGeneratorFromPairAndLayers classes to SeedingLayerSetNew
Migrate CombinedHitTripletGenerator to SeedingLayerSetNew
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 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