[www-apps/okupy] Multiple fixes:

Move from dev-python to www-apps
specify version in setuptools dep
Comply with django db useflags
Add REQUIRED_USE, at least one db is needed and tests need sqlite
Add set -- to actually fail the build when tests fail
Create local_settings.py, remove the sample config files,
create symlink of local_settings.py to /etc/okupy.py
Remove python_install_all since it was empty, will bring it back
as soon as okupy/static/ gets introduced in the code