CMIP7: adaptations to Classes representing stream info #605
Description
The CDDS plugins host default stream entries for projects (e.g. Amon/tas is usually in ap5 for CMIP6 style suites).
For CMIP7 we will have variables defined by more "facets" than mip table and variable name as in CMIP6; we will at least need to include frequency, and may need to include region (not sure yet)
Initially specifying the stream in the variables file is expected to avoid the StreamInfo and StreamStore code, but this will need work eventually.