Option enums with value in string, too

Discussed in GangSTAS 26.11.2024: some operators / detector experts like descriptive names like LOW_CDS, some like magical numbers (be they from control devices or from CalCat parameters) like 0.0. We can compromise and just put 0: LOW_CDS in the device. I'm not sure subclassing enum.Enum is a really good idea, but it seems to work. I'll just add a quick test of round-tripping the "parsing". Have checked, though, that JUNGFRAU and AGIPD can get constants and condition watcher is fine.

@schmidtp should I include this in today's deployment? If yes, will move tag. Note that it does add more user-facing changes. Especially because changing the options in schemata means saved configurations (notably, for standalone correction devices) will be wrong - something I can check and fix, but could overlook).