Delete RID_XMLSECTP_MACROWARN dialog

I deleted unused RID_XMLSECTP_MACROWARN and MacroWarning class.

Change-Id: Iaf0a99eae53b08a8a8869696ba19ae2023ede52a
Reviewed-on: https://gerrit.libreoffice.org/10718
Reviewed-by: David Tardon <dtardon@redhat.com>
Tested-by: David Tardon <dtardon@redhat.com>