Read version / build info

[joepio]

I want users to easily be able to see which version of Atomic-Server they're running. Of course there's --version, but that has some drawbacks:

• Can't be seen in the UI / front-end
• Doesn't work for specific build versions / sha hashes. Requires manual updates.

Let's consider some approaches:

• At build time, read an ENV (done by front-end and back-end) that contains the hash or date.
• Render it on the about page in the browser
• Include it in the version of CLI
• Maybe also include it on a new /about endpoint