Modernize the MS vertex finding algorithm

Modernisation changes and clean-up:

• Using smart pointers and references
• Changing to range-based for loops where possible

Using standard ATLAS helper functions:

• MuonIdHelperSvc instead of manual station selection
• xAODP4Helpers and AMG
• Gaudi properties and units

Added functionality:

• Global cartesian position of Tracklets
• Linking Tracklets to vertices
• Hits near the vertex split by layer

Fixes:

• inconsistency in MDT-station - B-field mapping to infer the tracklet momentum
• inconsistency in MDT sector assignment for tracklets

@jojungge, @obrandt, @mireveri

ATLASMCP-257