Add options for building OM3 libraries for CM3

[blimlim]

This issue is part of ACCESS-NRI/dev_coupling#56

We currently build CM3 via a multi-step process:

1. Build components MOM and CICE as libraries and other dependencies via the ACCESS-OM3 build ci. E.g as in this PR
2. Build the UM as a library locally via fcm. This is done as part of the suite.
3. Build CM3 locally using CMake. This is also part of the suite

In order to build libraries in step 1 that are suitable for steps 2 and 3, some small changes are needed to the access3 and access-cice spack packages. Specifically:

• We need to be able to add gcom as a dependency for CM3
• We need to be able to set the cice driver path as access/cmeps, rather than the default nuopc/cmeps used by OM3.

In the long term, I think we want to build CM3 in a single spack build. This needs to wait until a UM spack build is available, however the above changes should still be compatible with this long term goal.