Added link to video walkthrough to bb sso quickstart

Package Merge Request

Package Changes

• Small Diff Added link to video walkthrough to bb sso quickstart
• Note about work not done:
  Graham suggested embedding the video in the markdown. I tried other methods of embedding the video directly into the markdown page that were described on the following 2 pages, but I couldn't get them to work, so I just did what I did for the original quickstart
  https://docs.gitlab.com/ee/user/markdown.html
  https://about.gitlab.com/handbook/markdown-guide/#videos

Preview

https://repo1.dso.mil/platform-one/big-bang/bigbang/-/blob/sso_qs_vid/docs/guides/deployment_scenarios/sso_quickstart.md#video-walkthrough

For Issue

Subtask of https://jira.il2.dso.mil/browse/BBOI-1257