Concatenate & minify client assets

[ungoldman]

Currently we're sending 19 scripts and 8 stylesheets when serving the client assets. This is bad. Ideally should be 1 & 1. I'd also like to get rid of jquery & bootstrap.js and switch to using angular-bootstrap directives, but that's another issue.

I wasn't able to find anything like sprockets in the go package ecosystem that does this well yet, so unless server folks can provide a smart way to wrap this up I'll probably end up writing a script to do this that can be run as npm run build or something along those lines. Might end up moving the contents of static/app to a client directory that builds to static to keep things clean.

I'd rather not keep the built assets in version control as it will just be a bunch of minified noise, so if there any suggestions as to how to do that efficiently with the build process we have in place now please let me know (@aranasaurus @jyaganeh @CourtF).

[aranasaurus]

If you can make it be built via an npm command as stated, it'll be relatively simple to add that into our build script as well, and then just change which files get included in the tar