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 configuration: PostLS1_ConversionStep_cff
Migrate configuration: PhotonConversionTrajectorySeedProducerFromSingleLeg_gsf_cff
Migrate configuration: PhotonConversionTrajectorySeedProducerFromSingleLeg_cff
Migrate configuration: PhotonConversionTrajectorySeedProducerFromQuadruplets_cff
Migrate configuration: Phase1PU70_ConversionStep_cff
Migrate configuration: Phase1PU140_ConversionStep_cff
Migrate configuration: ConversionStep_cff
Migrate configuration: ConversionStep2_cff
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.