PISM related variables via IFS

[treerink]

The PISM (Greenland ice sheet) related variables in #143 are posted here as a separate issue:

To do (PISM related):  ImonGre  mrroLi       IFS Surface runoff grib 128.8 but for EC_Earth-GrIs additional melt etc is included
To do (PISM related):  LImon    sftgif       This is the land ice mask and will be an extra variable in IFS (thomas: via PEXTRA?)
To do (PISM related):  LImon    sftgrf       For Greenland this is the same as above sftgif. We do not have Antarctic ice sheet.
??                     LImon    sncIs        Not available in IFS. Although it could be calculated from tile fractions and written out as extra output

Assigned to: DMI / Shuting

[treerink]

Added to the cold cases

[treerink]

Activating this issue again (taking it off from the cold case list)