benchmark datasets

[brunosan]

For the linear probes, we are using c2smsfloods (#75). I'd like us to consider also other Sentinel-derived products:

• ESA's WorldCereal
• METER-ML
• Ctrees ( @fmacchiavello to clarify here if we can download an open-data global output).

[yellowcap]

Closing as out of date, feel free to re open if appropriate.