Merge remote-tracking branch 'xyan075/linearisation' into single_region_contact
Temporarily allowing the same mesh/field variables to be added to an interface/interface condition, multiple times

This would allow the projections to be evaluated within a single region.

Tracker Item 3675
Re-enabling InterfaceContactMetrics_Initialise

Tracker Item 3675
Allowing data reprojection in Problem_SolverNonlinearMonitor

This was required as, with the single region contact problem, no interface conditions are added to the solver equations.
Reprojection is only performed with PROBLEM_FINITE_ELASTICITY_CONTACT_TYPE problems.

Tracker Item 3675
Merge remote-tracking branch 'PrasadBabarendaGamage/single_region_contact' into linearisation

Conflicts:
	src/problem_routines.f90