Add CI build

[AlexanderRichert-NOAA]

Description

This PR adds a GCC11-and-MPICH-based CI workflow for building fv3atm, on top of which unit tests can be added. Dependencies are installed through Spack, where the installation directory is cached between runs for a significant speed up.

Issue(s) addressed

Addresses #729

Testing

Tested standalone build on personal machine and GH Actions. Built under ufs-weather-model on personal machine.

Dependencies

none

[edwardhartnett]

@junwang-noaa can you review this PR? This is needed for both documentation and unit testing work.

[edwardhartnett]

@AlexanderRichert-NOAA when the UFS is build by spack, is fv3atm one of the packages it builds?

Or does it build fv3atm as part of another package, using the git submodule method to get the fv3atm code?

[AlexanderRichert-NOAA]

The CMakeLists.txt of ufs-weather-model uses add_subdirectory(FV3), where FV3 is the name of the fv3atm repository, which is accessed as a git submodule.

[AlexanderRichert-NOAA]

Latest runs are at https://github.com/AlexanderRichert-NOAA/fv3atm/actions/runs/7414791796

[AlexanderRichert-NOAA]

@edwardhartnett if you're able to approve this I think it's good to go

[AlexanderRichert-NOAA]

@junwang-noaa can you recommend a second "approved" reviewer (I take it that Ed is not one)? If we can get this merged, I'll follow it up with the addition of the unit test infrastructure, including the first one or two unit tests.

[junwang-noaa]

@BrianCurtis-NOAA Dusan is on leave, I added you to review. Please note that other FV3 PRs may need to be synced when this PR is committed. Thanks

[BrianCurtis-NOAA]

i look forward to seeing how this works!

[AlexanderRichert-NOAA]

@junwang-noaa I believe this is ready to be merged