Container optimizations in preparation for OpenShift deployment

[jennydaman]

For the most part, this PR affects auxiliary files such as Dockerfile and docker-compose_dev.yml, as well as making some changes to configuration-related Python modules in config.

• mod_wsgi-express replaced by gunicorn
• manage.py collectstatic is run during build and served using WhiteNoise, easier deployment
• Base image replaced by Red Hat UBI (preferred over custom fnndsc/ubuntu-python3 image)
• Python version upgraded to 3.11 (from 3.8)
• Container user may be an arbitrary UID, closes Container security optimizations: arbitrary UID #514
  • UID build argument removed
• In docker-compose_dev.yml, database migrations are run in their own service. Advanced usage of depends_on imitates initContainer functionality, see Release notes 1.29 - initContainer information missing docker/docs#12633
• Entrypoint scripts docker-entrypoint.sh and migratedb.py are removed, they are no longer necessary
• Added an LDAP server to docker-entrypoint_dev.yml and enabled LDAP auth for config.settings.local

How I tested this:

• ✔️ ./make.sh all tests pass
• ✔️ ChRIS admin dashboard visible at http://localhost:8000/chris-admin/, seems to work
• ✔️ LDAP authentication works