Move Regridder functions to ClimaCore

[juliasloan25]

Some regridding functions are used by both ClimaCoupler and ClimaLSM. With the current setup, this code is duplicated in both repos. It should be moved to a shared location (i.e. ClimaCore), so that both repos can use the code without each having its own copy. This will make maintaining the code easier, and eliminate unnecessary redundancy.

This change will involve adding the relevant functions to ClimaCore, as well as updating ClimaCoupler and ClimaLSM to use this new interface.

[juliasloan25]

Update: This issue is replaced by the development of a new repo, ClimaUtilities.jl.