missing command line options in new app entrypoint

[evgeni]

Version
3.33.0

Describe the bug
in 4def68e a new app entrypoint was added to be used instead of calling gunicorn directly, however it is missing (at least) the --preload switch that gunicorn supports and Katello uses

https://github.com/benoitc/gunicorn/blob/master/gunicorn/config.py#L992

theforeman/puppet-pulpcore@b818946

To Reproduce
try to call pulpcore-content with --preload

Expected behavior
app boots

Additional context
Add any other context about the problem here. Please provide links to any previous discussions via Discourse or Bugzilla.