Update system diagram with CDN

[lbeaufort]

@patphongs and I have some questions about how CDN and routing currently work.

Completion criteria:

• [x] Double-check with cloud.gov (confirmed data flow is CDN > ALB > cloud.gov router. More docs:

  Feel free to review the network diagrams for the platform at the bottom of this page: https://cloud.gov/docs/compliance/diagrams/ The CF Docs on general Cloud Foundry routing. From the cloud.gov standpoint just follow along the HTTP traffic flow as we don't offer TCP Routing services: https://docs.cloudfoundry.org/concepts/cf-routing-architecture.html

• [x] Update the system diagram in the wiki 🔒 https://docs.google.com/drawings/d/13LtMZMlOyZlBurFLQZL8s2IyCN66kgu59c6FnC3Igto/edit 🔒
• [x] We should document how the CDN routing currently works

[patphongs]

Initial diagram 🔒 on DNS routing and CDN, still a WIP

[patphongs]

@lbeaufort I've updated the diagram with how I think the CDN fits into the system architecture: diagram 🔒

[lbeaufort]

@pat thank you! We should update the system diagram (https://github.com/fecgov/FEC/wiki/2.-FEC-system-diagram) with the non-ATO border image.

[lbeaufort]

Here's the doc without ATO border, but I had some questions about ALB and cloud.gov router. I believe the cloud.gov router routes traffic to an app, ALB balances that traffic between instances. We're going to check with cloud.gov in our next checkin, June 1.

From https://cloud.gov/docs/management/custom-domains/:

[lbeaufort]

Paired with @JonellaCulmer, now updated here: https://github.com/fecgov/FEC/wiki/2.-FEC-system-diagram