Code cleanup of InDetAmbiTrackSelectionTool (ATLASRECTS-3038)

Code cleanup of InDetAmbiTrackSelectionTool

• Move initialization to the header file using Gaudi Property.
• Sort includes.
• Replace tabs by spaces.
• Change indentation.
• Add space after if and for.
• Unify if-else style.
• Use nullptr instead of 0.
• Use default destructor.
• Use extends.
• Add override to inherit methods.
• Use range based for loop.

RunTier0Tests.py was fine. RunTier0Tests.log