Update ponds parameter implementation

[apcraig]

Remove icepack_init_sealvlpnd interface/subroutine

Move sea level pond parameter settings to icepack_tracers only temporarily.
Those values depend on the value of tr_pond_sealvl.  Eventually, these
parameters should either be removed and features should depend only on the
tr_pond_sealvl value or they should be move to namelist.

Change how "adjust pond iops if pond depth within specified range" logic
is handled.  Directly check tr_pond_sealvl instead of modifying hp0 to work
around that check.

Add some missing icepack abort checks in the new code.

Limited testing, verified baseline case and pondsealvl case built and ran on Derecho intel