v1.3.20 control proxy via  proxy-control object

By default AllegroServe's proxy has no restrictions on who can use the
proxy and which sites can be proxied. We introduce a proxy-control
object to allow one to specify who can use the proxy and how it can
be used.

<release-note>
allegroserve's proxy module can be controlled by proxy-control object
to prevent the proxy from being abused.
</release-note>

<documentation>
see rfe12300 for documentation on new proxy-control object
</documentation>

Change-Id: I9226bb9265245c260c814d45395fb8088bf3395f