allauth: Enable OpenID and Persona login support by default
allauth: Redesign the social account registration page
allauth: Document new features in the release notes

Also move it up in the roadmap.
allauth: docs: Document allauth/social auth support
allauth: Drop a redundant dir attribute
allauth: Disable third party authentication support by default

Support will be enabled and ready if users uncomment the apps in
INSTALLED_APPS.
Also document the allauth settings accordingly.