Add RFC4791 MKCALENDAR method
Merge pull request #15121 from skarpesh/rfc4791-methods

Add RFC 4791 MKCALENDAR method
fixes stack level too deep exception on action named 'status' returning 'head :ok'
Merge pull request #15118 from khelben/head_with_status_action_stack_level_too_deep

fixes stack level too deep exception on action named 'status' rendering 'head :ok'
formatting pass through CHANGELOGS. [ci skip]