Add API modifiers to limit returned toots from public/hashtag timelines

to only those from local users; Add link to "extended information" to
getting started in the UI; Add defaults for posting privacy; Change
how publish button looks depending on posting privacy chosen

config/locales/en.yml

@@ -97,8 +97,12 @@ en:
     settings: Settings
     two_factor_auth: Two-factor Authentication
   statuses:
-    over_character_limit: character limit of %{max} exceeded
     open_in_web: Open in web
+    over_character_limit: character limit of %{max} exceeded
+    visibilities:
+      private: Only show to followers
+      public: Public
+      unlisted: Public, but do not display on the public timeline
   stream_entries:
     click_to_show: Click to show
     favourited: favourited a post by

config/locales/simple_form.en.yml

@@ -23,6 +23,7 @@ en:
         note: Bio
         otp_attempt: Two-factor code
         password: Password
+        setting_default_privacy: Post privacy
         username: Username
       interactions:
         must_be_follower: Block notifications from non-followers