Surface info on outbound traffic with VPCs

Created by: DaedalusG

This change is intended to provide an answer to a customer inquiry:

networking questions! I'm assuming out system will need outbound network to • our okta installation • http://github.comgithub.com> (443 only?) • http://sourcegraph.comsourcegraph.com> for telemetry (443 only?)

I'm not the happiest with putting this change here in the docs, but I wasn't sure where else to surface this.

The intention here is to provide a quick answer for a potential FAQ in the interim. I am hoping CS can later develop a FAQ doc covering network setup questions generally pertaining to VPCs, VPNs, and Load balancing relating to SG. Our team will likely be addressing more networking questions under the purview of how-to in the future.