login_context now gets the social_backends list through
get_social_backend_dicts and we move display_logo customization
to backend class definition.
This prepares for easily adding multiple IdP support in SAML
authentication - there will be a social_backend dict for each configured
IdP, also allowing display_name and icon customization per IdP.
There are a few outstanding issues that we expect to resolve beforce
including this in a release, but this is good checkpoint to merge.
This PR is a collaboration with Tim Abbott.
Fixes#716.
Adblock Plus's "Block social media icons tracking" setting blocks
images with for social media platforms in their names from loading, so
we rename the Google logo to bypass this.
Dinesh
Mateusz Mandera
Rishi Gupta
synicalsyntax
Brock Whittaker