Add SoRad platform (medium term issue)

[oceancolorcoder]

Plymouth Marine Lab (PML) SoRad platform (with TriOS radiometer triplet) is to be added in 2024. This will include a RAW->L1A interpreter and provisions for instrument-specific and class-based corrections and uncertainties based on forthcoming instrument characterizations.

[oceancolorcoder]

So-Rad processing is well advanced and tested by PML and will be included in a release very soon. However, this is only for data pulled from the database rather than the incorporation of L1A HDF directly output from So-Rad (under development by PML Applications Ltd), so this issue will remain open.