Wireframe for 404 page

[morisy]

This should build off of #83.

Some things to consider while wire-framing:
-What would a user be doing before hitting this page?
-Where would a user want to navigate to once they hit this page ?
-What data should it contain? What is the most important pieces of data?
-How should this page look on different devices?

Acceptance Criteria:
Should have a detailed wire-frame of the 404 page that takes the above into consideration. Potentially could be posted in Slack where it can get some feedback, but since this is for an MVP prior to a bulk of user research, we don't want to go overboard in revisions.