Add list of muted user to UI and Getting Started (#1799)

Add the same UI that already exists for blocked users for muted
ones and add it to the "Getting Started" menu.

app/assets/javascripts/components/locales/en.jsx

@@ -31,6 +31,7 @@ const en = {
   "column.favourites": "Favourites",
   "column.follow_requests": "Follow requests",
   "column.home": "Home",
+  "column.mutes": "Muted users",
   "column.notifications": "Notifications",
   "column.public": "Federated timeline",
   "compose_form.placeholder": "What is on your mind?",
@@ -68,6 +69,7 @@ const en = {
   "navigation_bar.follow_requests": "Follow requests",
   "navigation_bar.info": "Extended information",
   "navigation_bar.logout": "Logout",
+  "navigation_bar.mutes": "Muted users",
   "navigation_bar.preferences": "Preferences",
   "navigation_bar.public_timeline": "Federated timeline",
   "notification.favourite": "{name} favourited your status",