Add swagger links to docs

[kristinapathak]

We may have the links somewhere, but I don't think so? We can either link the codex and xmidt/webpa swagger pages on their overview pages or add redirect pages to the left navigation under the correct projects.

[kristinapathak]

swagger links:
https://swagger.webpa.comcast.net/
http://swagger.codex.comcast.net/

folders:
https://github.com/xmidt-org/docs/blob/master/content/docs/webpa/
https://github.com/xmidt-org/docs/blob/master/content/docs/codex/

I think adding a page in each folder called swagger.md that has metadata that redirects to the swagger pages would be perfect.

An example of the metadata:
https://github.com/xmidt-org/docs/blob/master/content/docs/codex/fenrir.md

For ordering in the navigation, I think the swagger docs should be right below the "overview" page.

[kristinapathak]

Codex done in #37

Still need to figure out the path forward for the XMiDT and WebPA swagger pages.

[joe94]

Task: add opensource swagger page for webpa and xmidt (same style as codex's)