Restart read should confirm that each variable's subgrid level matches expectations

According to #1708 , I believe that @wwieder was able to restart the model using an initial conditions file where the SOIL10_VALUE variable's subgrid level differed between the restart file and the model. The model should abort in this situation with a meaningful error message, via an appropriate error check in either ncdio_pio or restUtilMod.

See also related issue #1709 .

Start by reviewing restart handling in ncdio_pio and restUtilMod, including how each variable's subgrid level is read and compared. Use the SOIL10_VALUE scenario from #1708 as a reference. Done means the model aborts with a meaningful error when any restart variable's subgrid level differs from expectations.

Written by the indexing model from the issue text.