Add documentation for event audit log
Add documentation for event audit log

jh23453/privacyidea,privacyidea/privacyidea,jh23453/privacyidea,privacyidea/privacyidea,jh23453/privacyidea,privacyidea/privacyidea,jh23453/privacyidea,jh23453/privacyidea,wheldom01/privacyidea,wheldom01/privacyidea,jh23453/privacyidea,wheldom01/privacyidea,wheldom01/privacyidea,wheldom01/privacyidea,privacyidea/privacyidea,privacyidea/privacyidea,wheldom01/privacyidea,privacyidea/privacyidea