Bring back net/php7X-xmlrpc from the new pecl xmlrpc package .
xmlrpc extension was removed from php 7.4  then later brougth back
as the pecl xmlrpc package. A direct copy from the php 7.4 source.
Place xmlrpc back in to Mk/Uses/php.mk _USE_PHP_ALL. Add logic to select
the proper xmlrpc php extension port base off version.