Configurations comparison table in README

[aekiss]

It could be helpful both for users and developers to have a comparison table between configurations in the README like what we have for ACCESS-OM3, to document their differences and make it easier to spot any inconsistencies.

Some suggested comparisons:

https://github.com/ACCESS-NRI/access-om2-configs/compare/release-1deg_jra55_ryf..release-025deg_jra55_ryf
https://github.com/ACCESS-NRI/access-om2-configs/compare/release-1deg_jra55_ryf..release-01deg_jra55_ryf
https://github.com/ACCESS-NRI/access-om2-configs/compare/release-025deg_jra55_ryf..release-01deg_jra55_ryf

https://github.com/ACCESS-NRI/access-om2-configs/compare/release-1deg_jra55_iaf..release-025deg_jra55_iaf
https://github.com/ACCESS-NRI/access-om2-configs/compare/release-1deg_jra55_iaf..release-01deg_jra55_iaf
https://github.com/ACCESS-NRI/access-om2-configs/compare/release-025deg_jra55_iaf..release-01deg_jra55_iaf

https://github.com/ACCESS-NRI/access-om2-configs/compare/release-1deg_jra55_ryf..release-1deg_jra55_iaf
https://github.com/ACCESS-NRI/access-om2-configs/compare/release-025deg_jra55_ryf..release-025deg_jra55_iaf
https://github.com/ACCESS-NRI/access-om2-configs/compare/release-01deg_jra55_ryf..release-01deg_jra55_iaf

https://github.com/ACCESS-NRI/access-om2-configs/compare/release-1deg_jra55_ryf..release-1deg_jra55_ryf_bgc
https://github.com/ACCESS-NRI/access-om2-configs/compare/release-025deg_jra55_ryf..release-025deg_jra55_ryf_bgc
https://github.com/ACCESS-NRI/access-om2-configs/compare/release-01deg_jra55_ryf..release-01deg_jra55_ryf_bgc

https://github.com/ACCESS-NRI/access-om2-configs/compare/release-1deg_jra55_iaf..release-1deg_jra55_iaf_bgc
https://github.com/ACCESS-NRI/access-om2-configs/compare/release-025deg_jra55_iaf..release-025deg_jra55_iaf_bgc
https://github.com/ACCESS-NRI/access-om2-configs/compare/release-01deg_jra55_iaf..release-01deg_jra55_iaf_bgc