Add support of Huawei Object Storage Service (OBS)

[Sergei]

Extends smart_open to support Huawei Object Storage Service.

Motivation

Currently I`m working on enhancement of Ray for ability execute applications stored as archive in OBS.
It requires extending smart_open to support OBS.
I prepared PR for smart_open.
I would be very grateful if you would accept this change.
@mpenkov