[Glitch] Add explanation to mute dialog, refactor and clean up mute/block UI

Port 9027bfff0c to glitch-soc

Signed-off-by: Thibaut Girka <thib@sitedethib.com>

app/javascript/flavours/glitch/reducers/index.js

@@ -16,6 +16,7 @@ import local_settings from './local_settings';
 import push_notifications from './push_notifications';
 import status_lists from './status_lists';
 import mutes from './mutes';
+import blocks from './blocks';
 import reports from './reports';
 import contexts from './contexts';
 import compose from './compose';
@@ -53,6 +54,7 @@ const reducers = {
   local_settings,
   push_notifications,
   mutes,
+  blocks,
   reports,
   contexts,
   compose,