Use dput-ng to upload to debusine and start a workflow

We want to offer an interface for Debian developers that is very close to their current experience, so we want them to be able to use dput to upload a source package to debusine and trigger the new workflows, and then control the rest of the process from within debusine.

$ dput debusine.debian.net foo_1.2-3_source.changes
...
Workflow has been started: https://debusine.debian.net/...

Some comments:

• We can possibly ship everything required in debusine-client directly:
  • /etc/dput.d/profiles/debusine-debian-net.json
  • /etc/dput.d/uploaders/debusine.json
  • /etc/dput.d/metas/debusine.json
  • /usr/lib/python3/dist-packages/dput/uploaders/debusine.py
• In the profiles file, some mapping are obvious:
  • fqdn: the debusine hostname
  • incoming: could be used to document the "scope/workspace" to use
• Some thoughts needs to be put in how we manage the mapping from the distribution in the .changes to the workflow to execute on the other side. Maybe we need to invent a new configuration file, and/or hardcode the value for debusine.debian.net for now.