Alkalinity deposition flux

[nikizadehgfdl]

• This updates add wet and dry deposition fluxes for tracer alk and
  registers diagnostics for them

• This update by itself should not change anything in the models. It only prepared COBALT to receive the alk fluxes when the ATM alkalinity fluxes are ready and sent down.

• atmos_phys repo branch alkalinity_deposition_flux atmos_dust.F90
  prepares these fluxes on the ATM side to be received by alk.

• Currently these fluxes are set to 0 till the alkalinity content of
  dust fluxes is formulated in line 956 of atmos_dust.F90

• John Dunne wrote:
  "I have been talking with Charlie and Jasmin about running some ESM4.2
  simulations where we add purposefully add alkalinity to the ocean induce
  Carbon Dioxide Removal from the atmosphere, and we think the most
  code-efficient way to do it would be to add connectivity thought the
  coupler like we do for NO3 and Fe. Would you be able to help me with
  this? The default would be to assign a zero flux over the ocean, and
  the data override would be to assign a map of wet or dry deposition as
  an alkalinity flux. Jasmin and I discussed an alternative of creating a
  3D data override flux within the COBALT code, but upon further thought I
  believe that approach would both be much more work and less applicable
  to the long term goal of being able to simulate potential alkalinization
  of the atmosphere (which I think will also be proposed soon)."

• There is also an unrelated minor change in generic_tracer_utils to allow using newer versions of MOM6

[nikizadehgfdl]

I made a PR to atmos_phys for the sending end of these fluxes
https://gitlab.gfdl.noaa.gov/fms/atmos_phys/-/merge_requests/33