Expose public libraries and channels in standard API

api/funkwhale_api/federation/dynamic_preferences_registry.py

api/funkwhale_api/federation/serializers.py

api/funkwhale_api/federation/urls.py

api/funkwhale_api/federation/views.py

api/funkwhale_api/instance/nodeinfo.py

api/tests/federation/test_views.py

api/tests/instance/test_nodeinfo.py

front/src/views/admin/Settings.vue