When search enabled, display hint in search popout (#6593)

* When advanced search is enabled, show different hint in search popout

* Change "getting started" icon in tabs bar from asterisk to hamburger

app/javascript/mastodon/initial_state.js

@@ -10,5 +10,6 @@ export const unfollowModal = getMeta('unfollow_modal');
 export const boostModal = getMeta('boost_modal');
 export const deleteModal = getMeta('delete_modal');
 export const me = getMeta('me');
+export const searchEnabled = getMeta('search_enabled');
 
 export default initialState;