[snowpatch] snowpatch for upstream Patchwork

[Russell Currey]

snowpatch at present supports the freedesktop.org fork of Patchwork as it was
the first codebase that had series support, along with a REST API.  The upstream
Patchwork project has the API and will have series support at some point in the
future, and in order to maximise snowpatch's usefulness in the community, we
will be moving to support upstream Patchwork.

This means snowpatch will no longer be usable with the fork.

In order to get started even though upstream Patchwork does not have series, I
am going to implement support by treating individual patches as "series", with
the intent of replacing this with the series API when it exists.  This gives us
the benefit of being able to work on snowpatch with existing Patchwork instances
so that when series does arrive, we can hit the ground running.

I will be posting a lot of patches soon, which will rip out the old and put in
the new.  For those that have not worked with Patchwork before, creating a
development instance of upstream Patchwork is very easy now that there's a
Docker configuration, and I would hugely appreciate any testing.

- Russell