Simplify setting (max) cloud coverage in load_collection

[soxofaan]

Setting max cloud cover can be quite important when loading a collection (e.g. to avoid loading unusable raw data).
It's currently however quite cryptic to do that with the python client:

cube = connection.load_collection(
    ... , 
    properties={"eo:cloud_cover": lambda v: v == 80}
)

There should be a user friendly shortcut (e.g. a dedicated Connection.load_collection argument to lower the bar to use this, and promote usage.

[soxofaan]

a1a35c9 added max_cloud_cover argument to load_collection:

cube = connection.load_collection(
        "S2",
        max_cloud_cover=75,
    )