Fix leaking private configuration parameters in Mastodon and Twitter APIs, and add new configuration parameters to Mastodon API

This patch:
- Fixes `rights` in twitterapi ignoring `show_role`
- Fixes exposing default scope of the user to anyone in Mastodon API
- Extends Mastodon API to be able to show and set `no_rich_text`, `default_scope`, `hide_follows`, `hide_followers`, `hide_favorites` (requested by the FE in #674)

Sorry in advance for 500 line one commit diff, I should have split it up to separate MRs

lib/pleroma/user/info.ex

@@ -227,14 +227,6 @@ defmodule Pleroma.User.Info do
     cast(info, params, [:confirmation_pending, :confirmation_token])
   end
 
-  def mastodon_profile_update(info, params) do
-    info
-    |> cast(params, [
-      :locked,
-      :banner
-    ])
-  end
-
   def mastodon_settings_update(info, settings) do
     params = %{settings: settings}