Enable sites to run different sets of recipes in RTW

[ehogan]

All recipes must be added to the RTW in preparation for the v2.12.0 release. However, since the list of recipes in the RTW are not site-specific, all recipes would run on all sites. Consider the following:

• 10 new recipes are added to the RTW so that they run on DKRZ (i.e. with resources and KGOs)
• The changes are committed to main
• The main version of the RTW is run at the MO
• All the newly added recipes fail because resources are not defined (and the default resources are not sufficient) and no KGOs exist at the MO

The RTW must be updated so that different lists of recipes are run at different sites.

[ehogan]

Oh dear, apparently there is already an issue open for this (#3724); sorry about that! 😱