Add regex filters on the community timeline and the public timeline. (#3564)

* Add regex filter on the community timeline and the public timeline

* correcting

* Adjust the height of header buttons

* Remove trailing spaces

* Remove trailing spaces

* Solve some code duplication

* reset the state of the locale files in app/javascript/mastodon/locales

* adjust to upstream

* adjust to upstream

* change keys of locale settings

app/javascript/mastodon/reducers/settings.js

@@ -46,6 +46,18 @@ const initialState = Immutable.Map({
       mention: true,
     }),
   }),
+
+  community: Immutable.Map({
+    regex: Immutable.Map({
+      body: '',
+    }),
+  }),
+
+  public: Immutable.Map({
+    regex: Immutable.Map({
+      body: '',
+    }),
+  }),
 });
 
 const moveColumn = (state, uuid, direction) => {