Feature request: MOM6 clamping

[hkershaw-brown]

Use case

What are you trying to accomplish? Sometimes there may already be a way to do what you need.

MOM6 model_mod followed POP which does not give the users the option to clamp state values on write.

MOM6 DA users are clamping very cold ocean values,
main...mom6-clamp

Is your feature request related to a problem?

Ocean temp values going very cold, like -100C.

Describe your preferred solution

The users want to clamp (hence branch with clamping for them)
Note this is a namelist change, so will break existing runs.

Describe any alternatives you have considered

I am not sure why clamp rather than qceff bounds.

[hkershaw-brown]

Note main...mom6-clamp has changes for use_pseudo_depth = .true. - I do not think we want this as the default. This branch was just a demo of required changes.

[hkershaw-brown]

Bundle this with the units change because two breaking changes are better at once?