Add 'has' ACL

Add 'has' ACL

This ACL detects presence of request, response or ALE transaction
components. Since many ACLs require some of these components, lack of
them in a transaction may spoil the check and confuse admin with
warnings like "... ACL is used in context without an HTTP request".
Using 'has' ACL should help dealing with these problems caused by
component-less transactions.

Also: addressed TODO in item #3 of v4 revision 14752.