[FrancescAlted]

This adds a new Array protocol that is useful to describe the minimal interface that should be supported for blosc2 functions to deal with array inputs. This protocol is really minimal, and it does not actually depend on any non-standard array API method or property (like .chunks); @lshaw8317 hope this is fine for most (if not all) the signature changes proposed here, but if not, we need to discuss which cases require a more complete interface (blosc2.ChunkedArray ?).

So instead of describing the input types as e.g. NDArray | NDField | C2Array | LazyArray, they are described now as blosc2.Array.

As a plus, and thanks to the @runtime_checkable decorator, compliance with the new Array protocol can be tested at runtime with isinstance(object, blosc2.Array).