Redesign authorities management to allow only for selecting it from file (not raw pasting)

• Removed the option to define authority by pasting its value. Now it's only possible to select a file that contains authority definition.
• Due to the redesign of authorities management some bugs were fixed. For example, there were problems with editing an existing authority (after saving, the old one was still present in the ManageAuthorities screen). Also deleting was not ideal since indexes were different right after deletion and when reloading the ManageAuthorities screen. Now authorities list is rebuilt after some actions and there are no such problems.