Merge pull request #653 from nextcloud/feature/gravatar-opt-out

appinfo/routes.php

js/app.js

js/radio.js

js/service/preferenceservice.js

js/templates/settings.html

js/tests/service/preferenceservice_spec.js

js/views/settings.js

lib/AppInfo/Application.php

lib/Contracts/IUserPreferences.php

lib/Controller/PageController.php

lib/Controller/PreferencesController.php

lib/Service/Avatar/AddressbookSource.php

lib/Service/Avatar/CompositeAvatarSource.php

lib/Service/Avatar/FaviconSource.php

lib/Service/Avatar/GravatarSource.php

lib/Service/Avatar/IAvatarSource.php

lib/Service/AvatarService.php

lib/Service/UserPreferenceSevice.php

templates/index.php

tests/Controller/PageControllerTest.php