Add an exchange module for the MCT

[AntoniaBerger]

Fixes #252

Work structure:

• [x] #256
  • [x] New Base class 'IPhaseTransition Model'
  • [x] New class 'LinearExchange'
  • [x] Add to CMakeList
  • [x] #262
  • [x] Compare exchange modul results with implemented version.
• [x] Add exchange as a part of the MCT modul
  • [x] make exchange parameter parameter part of MCT
  • [x] ubdate parameter handler for phaseTransitionModel
  • [x] Test results
• [x] Outsourse Iteration and declaration for residual and Jacobian?