chore(server): Various application clean up.

[ryan-roemer]

• Move application source to src to clarify files. Leave server as-is
• Add a new logo/profile
• Search on other TODOs in app and either fix or ticket.
• Memoize retrieving the post data and post content? (Doesn't seem to be a big deal)
• We're not doing any routing in express, with the Next.js router doing it all. Try out removing express and using http built-in module instead. (Fix or ticket) (Not doing because we use express.static() in root handler.