We've been having mm3 web ui slowness recently and noticed that we only
have 2 uwsgi processes with 2 threads each for a total of 4 concurrent
requests being handled at once.
This is potentially the source of some of our slowness as the site gets
crawled by all the things taking uwsgi thread slots from interactive
users. Double the process count to see if it helps. We start small as it
is possible this will make things worse if the problems are further
downstream.
Note to do this we modify the mailman3 role to bind mount a modified
uwsgi.ini into the mailman-web container rather than modifying the
config file within our images. This allows us to keep the containers in
sync with upstream while still supplying our overridden values.
Change-Id: I14c0c98d1d7dd4e2b8b22779a0e37b37a0124681
265f245ebb