The fw-bot testing API should improve the perfs of mergebot tests
somewhat (less waiting around for instance).
The code has been updated to the bare minimum (context-managing repos,
change to PRs and replacing rolenames by explicit token provisions)
but extra facilities were used to avoid changing *everything*
e.g. make_commit (singular), automatic generation of PR refs, ...
The tests should eventually be updated to remove these.
Also remove the local fake / mock. Being so much faster is a huge
draw, but I don't really want to spend more time updating it,
especially when fwbot doesn't get to take advantage. A local /
lightweight fake github (as an external service over http) might
eventually be a good idea though, and more applicable (including to
third-parties).
Converge the pytest setups of runbot_merge and forwardport a bit
more (the goal is obviously to eventually share the infrastructure so
they run the same way).
This is the preparation of an attempt to make these tests work with
both a local github mock (in-memory) and a remote actual github.
Move a bunch of fixtures relying on the specific github
implementation (and odoo-as-library access) to the "local" plugin,
including splitting the "repo" fixture.
The specific fixtures will likely have to be adjusted as the
remote endpoint is fleshed out.
