New BLOM with CMIP6 settings

Users may want to run new versions of BLOM/iHAMOCC, but retain a model state as close to CMIP6 as possible.

Run Noresm2.1 with BLOM tag v1.6

The settings below result in bfb-identical circulation state to CMIP6, while iHAMOCC doesn't due to bug-fixes (i.e. dust sinking and sediment alkalinity).

1. Check out the latest NorESM2.1 version, and replace the blom tag with the latest tag on the release-1.6 branch (e.g. v1.6.2)

2. Set units to the CGS standard

./xmlchange BLOM_UNIT=cgs

3. Set entries in the user_nl_blom file

For resolution T62_tn21:

EDANIS = .false.
EDDF2D = .false.
EDSPRS = .true.
RHSCTP = .false.
EGC = 0.5
EGMNDF = 100.e4     
EGMXDF = 1000.e4
RHISCF = 0.

For resolution T62_tn14:

EDANIS = .false.
EDDF2D = .false.
EDSPRS = .true.
RHSCTP = .false.
EGC = 0.85
EGMNDF = 100.e4     
EGMXDF = 1500.e4
RHISCF = 0.