Move CMEMS insitu from copernicusmarine files service to subset once available

[veenstrajelmer]

The cmems insitu data is used by the functions demonstrated in subset_retrieve_sealevel_observations.ipynb

Todo:

• CMEMS INSITU is in early phase and spatial subsetting via CMEMS API is expected mid2024. See email from Irene/CMEMS from 13-06-2023.
• Move CMEMS insitu from copernicusmarine files service to copernicusmarine subset once insitu data is available there: import copernicusmarine; copernicusmarine.open_dataset(dataset_id="cmems_obs-ins_glo_phy-ssh_my_na_PT1H") currently raises "NoServiceAvailable: No service available for dataset with command load", later it raised "FormatNotSupported: Subsetting format type sqlite not supported yet."
• Check with copernicusmarine developers whether subsetting in both time and space is possible on the "station catalog" (without downloading data, so real quick), preferrably also on slev variable (or any other) and on country_code (or edmo_code if country_code is really not possible). This can also be achieved via an online available json file, but the copernicusmarine toolbox can probably also offer this functionality.
• update copernicusmarine minimal version