MDL-21696 removing old translation UI which can not work any more + removing unused string_manager code

lib/moodlelib.php

@@ -5904,13 +5904,6 @@ class amos_string_manager implements string_manager {
         return $this->load_component_strings('countries', $lang);
     }
 
-    /**
-     * TODO: this will be probably removed soon
-     */
-    public function get_registered_plugin_types() {
-        error('to be removed soon');
-    }
-
     /**
      * TODO: will be removed really soon
      */
@@ -5941,11 +5934,6 @@ interface string_manager {
      */
     public function get_list_of_countries();
 
-    /**
-     * TODO: this will be probably removed soon
-     */
-    public function get_registered_plugin_types();
-
     /**
      * TODO: will be removed really soon
      */
@@ -6024,19 +6012,6 @@ class legacy_string_manager implements string_manager {
         $this->showstringsource = $showstringsource;
     }
 
-    /**
-     * This returns an array of all the types of plugin that may have language
-     * strings.
-     *
-     * The array keys are the lang file prefix, like qtype_, and the value is
-     * an array of paths relative to $CFG->dirroot.
-     *
-     * @return array as described above.
-     */
-    public function get_registered_plugin_types() {
-        return fullclone($this->searchplacesbyplugintype);
-    }
-
     /**
      * Returns an array of locations to search for modules
      *