add compressors, filters, serializer to Array as attributes

[d-v-b]

#2463 added a new function for creating arrays that abstracts over the painful fact that v2 arrays and v3 arrays have overlapping-but-distinct specifications of how chunks are encoded. This function expresses the v2 and v3 chunk encoding specs via 3 keyword arguments:

• filters (filters in v2 , the array_array_codecs elements of the codecs list attribute in v3)
• serializer (implicit in v2, the array_bytes_codec element of the codecs list attribute in v3)
• compressors (compressor in v2 (note the singular), bytes_bytes_codec elements of the codecs list attribute in v3)

logically, these terms describe "transformations made to chunks when they are n-dimensional arrays", "the transformation that turns an n-dimensional array into a flat bytestream", and "transformations made to chunks after they are flattened to bytestreams"

but we don't expose filters, serializer, compressors as attributes on the Array class, which is probably where users will expect to find them. So I'm proposing that we add filters, serializer, compressors to the Array class.