Update python-django to 4.2.6
    
    - Use python3-memcached instead of pylibmc for memcached backend
    - Disable doc generation as Sphinx provided by CRB (3.4.3) is
    below 4.5 [1]
    - Remove unneeded deps
    - Remove mysql and oracle deps
    - Remove old patches
    
    4.2.6 is not current u-c version but it's the most updated one
    built in Fedora.
    
    [1] https://github.com/django/django/commit/ebf25555bbed3e9112d4b726575d60b242daf48a
    
    Related-to: https://review.rdoproject.org/r/q/I405b7000b2f6725d35ed1140c88944a3576c7278