[cleanup] Remove deleting/undeleting APISite methods
[cleanup] Remove deleting/undeleting APISite methods

Remove deletepage, deleteoldimage, undelete_page, undelete_file_versions
in favour of delete and undelete methods. All are deprecated since 6.0.1.

Change-Id: I966ec6d3b97340eb37b78ceed48eb0c1dfac6dff

wikimedia/pywikibot-core,wikimedia/pywikibot-core