Restart: fix reading restart without orginal input files

When starting from restart file, the original input files were still read.

That means, that:

• nLAI and LAIBoundaries need to be read from restart before initializing arrays
• level0 information need to be written to and read from mHM restart file
• mpr input should not be read.

Also, the following arrays were not LCover dependent:

• L1_alpha (used in mpr_runoff)
• L1_kSlowFlow (used in mpr_runoff)
• L1_kBaseFlow (depends on L1_kSlowFlow)
• L1_Perco (used in karstic_layer)

The following variables can now be 2D or 3D in the restart file (for backward compatibility):

• L1_alpha
• L1_kSlowFlow
• L1_kBaseFlow
• L1_Perco
• L1_degDay (Ulysses restart file compatibility)

Also there was a name compatibility added for L1_kFastFlow, that could be named "L1_kFastFlow" or "L1_kfastFlow" in the restart file. (Ulysses restart file compatibility)

Check case reference files were rewritten accordingly.

Addition changes:

• a new flag was added to the mainconfig_mhm_mrm namelist in mhm.nml:
  • restart_reset_fluxes_states: if you want to reset fluxes and states read from restart to default values
• L0Domain is now checked to be set up correct (documentation in mhm.nml updated)