Merge remote-tracking branch 'origin/master' into gs-master

Conflicts:
 	app/serializers/initial_state_serializer.rb

The glitch flavour isn't yet pulling custom emoji data on its own (see
https://github.com/tootsuite/mastodon/pull/7047).  Once that gets into
the glitch flavour, we can eliminate the custom_emojis load.

config/initializers/stoplight.rb

@@ -0,0 +1,3 @@
+require 'stoplight'
+
+Stoplight::Light.default_data_store = Stoplight::DataStore::Redis.new(Redis.current)