Add information on setting "warm restart date" in CM2

[anton-seaice]

Description

Users often want to restart CM2 from different times in an existing run, for example, to branch off from the access CMIP6 output. How to set this is not covered in the CM2 "how to run a model" page.

Why

As highlighted in https://forum.access-hive.org.au/t/changing-the-restart-year-for-branched-cm2-ensembles/3961, its not totally clear how to start a model run from existing restart files (like those provided from CMIP6 runs). There should be another short section in the doc with how to change the restart date for CM2.

Close Criteria

New short section in the CM2 how to run a model page.

[access-hive-bot]

This issue has been mentioned on ACCESS Hive Community Forum. There might be relevant details there:

https://forum.access-hive.org.au/t/changing-the-restart-year-for-branched-cm2-ensembles/3961/5

[atteggiani]

Hi @anton-seaice , thank you for raising this issue.

That's a valid point, and I think it needs to be addressed.
However, I think it would be best to do it together with the re-work of the "How to run ACCESS-CM2" page after the official ACCESS-CM2 release by ACCESS-NRI (which has not happened yet and should be happening within this year).