Test more gevent workers per app instance

[lbeaufort]

1G app = 4 CPU cores
(cf ssh api -i 0 to log into one app instance, cat /proc/cpuinfo to see cores)
https://docs.gunicorn.org/en/stable/run.html#commonly-used-arguments

Recommended workers is 2xCPUs+1 = 9 workers (currently 4 workers)

Completion criteria

• Take a baseline locust test of dev at 10 instances, note database CPU and connections start/end
• Update gunicorn --access-logfile - --error-logfile - --log-level info --timeout 300 -k gevent -w 9 webservices.rest:app to -w 9
• Take an "after" locust test of dev , note database and connections CPU start/end

-- Check the number of workers with ssh api and ps aux | grep gunicorn | grep -v grep | wc -l (subtract one) per https://stackoverflow.com/a/33107962

I couldn't get gunicorn to recognize the WEB_CONCURRENCY or GUNICORN_CMD_ARGS env vars.