[Python] Support constructing dictionary array directly through pa.array()

[asfimport]

pa.array(["some", "string"], type=pa.dictionary(pa.int8(), pa.string)))

raises

ArrowNotImplementedError: Sequence converter for type dictionary<values=string, indices=int8, ordered=0> not implemented

It would be a much more comfortable way than

pa.DictionaryArray.from_arrays(indices, dictionary)

And possibly more efficient as well thanks to the adaptive dictionary builders.

Reporter: Krisztian Szucs / @kszucs
Assignee: Krisztian Szucs / @kszucs

Related issues:

• [C++][Python] Refactor python to arrow conversions based on a reusable conversion API (is fixed by)

_{Note: This issue was originally created as ARROW-9999. Please see the migration documentation for further details.}