Remove real land/sea/ice mask, use integer variable instead

[climbfuji]

Description

The ccpp-physics code uses both real and integer land/sea/ice masks, mostly due to legacy code from different modeling systems (WRF, GFS).

There is no need for a type real land/sea/ice mask, which by definition takes integer values 0, 1, 2, ...

Your mission, should you choose to accept it, is to rewrite the physics schemes to use the integer land/sea/ice mask and terminate the real land/sea/ice mask. This issue will never self-destruct. It will stay up until someone completes the task.

[climbfuji]

Same for soil_type_classification_real/soil_type_classification and vegetation_type_classification_real/vegetation_type_classification

[ligiabernardet]

After this work is done, make sure the dictionary of standard names (https://github.com/ESCOMP/CCPPStandardNames) is updated accordingly (that is, remove standard names that end in _real).