Algorithm cleaning when running in fast tracking configuration

Changing the configuration of few algorithms to avoid spending CPU when not needed, in the context of fast track reconstruction:

• Removing InDetTrackCollectionMerger, as not needed for fast tracking (can be tuned later on if running with multiple passes is needed);
• Removing HoleSearchTool in the configuration of the TrackSummaryTool, to avoid evaluation of precise holes as they are not used in track reconstruction (only pattern holes are used in track finding);
• Implementing fitting algorithm to test the machinery and switched off by default (not meant to run in fast track recostruction).

FYI: @tstreble, @nstyles, @tadej, @asalzbur, @iene, @hgray