Add a date range feature

[Florian-BACHO]

Hi,

Nice work on this component!

I suggest adding a parameter for allowing the selection of date ranges.
Maybe something like:

Calendar(type="datetime", label="Select a date range", range=True)

or

Calendar(type="datetime", label="Select a date range", mode="range")

The predict function could then have the following signature:

def predict(
    value: str | datetime.datetime | tuple[str, str] | tuple[datetime.datetime, datetime.datetime] | None
) -> str | datetime.datetime | tuple[str, str] | tuple[datetime.datetime, datetime.datetime] | None:
    return value