Remove use of DIN_LOC_ROOT_CLMFORC and use softlinks when needed for multiple disks for inputdata

[ekluzek]

trafficstars

We want to deprecate and remove DIN_LOC_ROOT_CLMFORC in CESM and use softlinks for cases where inputdata needs to reside on multiple disks.

The parent issue for this is in cime here:

https://github.com/ESMCI/cime/issues/3097