let fre cmor run process tripolar ocean data

[ilaflott]

this PR will ideally enable fre cmor run to process ocean data on a native tripolar grid. also will do some general clean up here and there. relevant background: #268 PCMDI/cmor#766 and PCMDI/cmor#767

Describe your changes

• remove GitPython pip-only dependency that can only be fulfilled by terrible habits
• add PCMDI/cmip6-cmor-tables as submodule dependency
• set minimum python version to 3.10 minimum
• ... more to come ... work-in-progress ...

Issue ticket number and link (if applicable)

will close #298 (ideally)

Checklist before requesting a review

• I ran my code
• I tried to make my code readable
• I tried to comment my code
• I wrote a new test, if applicable
• I wrote new instructions/documentation, if applicable
• I ran pytest and inspected it's output
• I ran pylint and attempted to implement some of it's feedback

[ilaflott]

so asking conda/mamba to use python3.10 or greater is surprisingly an issue. Dinking around with this locally, the first thing it complains about is cylc-uiserver. Given that this has yet-to-be-utilized in the actual repository, I comment it out.

The next issue is catalogbuilder... actually, really, a requirement of catalogbuilder's. intake-esm==2023.7.7, which seems to desire a python of 3.9 or less, but 3.9 is nearing EOL.

Given that this quick python version bump was supposed to be a quick-sidequest, i'll be restoring the dependencies and barking up that tree some other time.

[ilaflott]

every now and then, a random conda build fails... here, it claims import git is causing the failure. I did remove that module, but i also removed that line

edit: same failure, same job. sanity demanding i ignore the conda_build workflow for a minute apparently

edit2: same failure, different job. xmas nightmare! moving on...