remove chowns from image entrypoint
remove chowns from image entrypoint

these `chown` calls seemed useful to ensure that mounted volumes come in with
the correct permissions. they don't really work out in practice. deployment
platforms have their own mechanisms for setting volume permissions at mount
time. it's best to use them.

samvera/hyrax,samvera/hyrax,samvera/hyrax,samvera/hyrax