Allow user to disable the boost confirm dialog in preferences

app/views/home/initial_state.json.rabl

@@ -5,6 +5,7 @@ node(:meta) do
     access_token: @token,
     locale: I18n.locale,
     me: current_account.id,
+    boost_modal: current_account.user.setting_boost_modal,
   }
 end
 

app/views/settings/preferences/show.html.haml

@@ -22,5 +22,8 @@
     = ff.input :must_be_follower, as: :boolean, wrapper: :with_label
     = ff.input :must_be_following, as: :boolean, wrapper: :with_label
 
+  .fields-group
+    = f.input :setting_boost_modal, as: :boolean, wrapper: :with_label
+
   .actions
     = f.button :button, t('generic.save_changes'), type: :submit