Hard code scale variation theories in validphys

[Zaharid]

I think that having to remember and write the various scale variation theory ids in each fit gets error prone quickly, makes the runcards harder to read write and check. I think we should be able to write something like:

scale_variations_for:
   theoryid: 163
   kind: '9 point'

and have a production rule of some sort that resolves that to:

   theoryids:
      - 163
      - 177
      - 176
      - 179
      - 174
      - 180
      - 173
      - 175
      - 178

In such a way that loader.check_theoryid is called so the theories are downloaded if needed and so on. I think this is expected to be stable enough that we can just hardcode it into validphys without worrying too much about complicated backwards compatibility mechanisms.