Finish register diag

[uramirez8707]

Description
This PR:

• Changes the fms_register_diag_field_obj arguments by adding diag_field_indices, so that the diag_field yaml can be added to the diag_obj, and makes axes public, so that this interface can be used for scalar and array variables. This breaks the test_diag_object_container, so the test is no longer compiled. This will need to be removed later.
• Sets up an array of subaxis_t objects to store any sub axis for sub_regions
• Adds the domain and sub_axis info to the diag_file_obj
• Completes (almost!) the register_diag_field work! Just need to fill in the var_reg, var_ids and var_index part of the diag_file object and the sub_regional stuff still needs to be set up

Fixes # (issue)

How Has This Been Tested?
CI

Checklist:

• My code follows the style guidelines of this project
• I have performed a self-review of my own code
• I have commented my code, particularly in hard-to-understand areas
• I have made corresponding changes to the documentation
• My changes generate no new warnings
• Any dependent changes have been merged and published in downstream modules
• New check tests, if applicable, are included
• make distcheck passes