rcstream: add DNS records for stream.w.o

Adding the stream-lb.eqiad load balancer and stream.w.o CNAME to it.
See RT #7551 for more details.

Change-Id: I02e8aab25dbf1835ef1b3e306e81b90212a007e2
Signed-off-by: Giuseppe Lavagetto <glavagetto@wikimedia.org>