Split off snapshot fields from registry

[jimmielin]

What is the feature/what would you like to discuss?

As physics schemes are ported more fields are being introduced into registry.xml that are solely for the purpose of reading these fields in from the snapshot (pbuf or tphysac/tphysbc) fields.

To avoid clutter in registry.xml, these could be split off into a separate file, and the generated code for handling those might also potentially be separated into separate modules.

Other notes from CAM-SIMA planning meeting about this:

• @nusbaume pointed out that a snapshot registry may still be needed in the future for single-column CAM applications, as these model runs do not provide the full model state.
• @cacraigucar suggested adding a line in registry.xml now to split off the snapshot variables from the rest.

Is there anyone in particular you want to be part of this conversation?

@cacraigucar @peverwhee @nusbaume

Will this change (regression test) answers?

No

Will you be implementing this enhancement yourself?

Any Software Engineer can do this