Integrate MantleAPI v12

- Reimplement deleted Mocks that return other mocks on e.g.
GetEntityRepository() in test/TestUtils.h as Fake classes
- Replace mocks with fake classes in tests
- fix wrong usage of (local) LaneIds and (global) UniqueId for lanes in
LateralDistanceAction and ConvertScenarioAbsoluteTargetLaneTest
- adjust to new getter for entities (weak ptr instead of optional
reference wrapper)
- entities in the repo are now shared ptr instead of unique ptrs (for
tests)
- adjust to new route handling (removed AssignRoute(), add Create() in
route repository
and SetRoute() in entity)
- adjust to renaming of members in route definition
- adjust to redefinition of polynomial in SplineSection (struct instead
of tuple)
- fix namespace for MockStatistics