Use site-specific lists of recipes in the RTW

[ehogan]

I realised as I was adding recipes to run on DKRZ (via #3708) that those recipes would not be able to run at other sites, since the resources wouldn't be defined (so the recipes would likely run out of time and / or memory, using the default resources).

After a quick discussion with @alistairsellar, we agreed to use site-specific lists of recipes (@alistairsellar mentioned that the RTW running on JASMIN began to fail due to recent additions of recipes that were introduced at the MO).