Replace npm/bower with uncss'ed CSS and its script

So the script could possibly do with some comments.

I touch the uncss'ed file, so that it exists when uncss parses the
template, because if uncss can't find it, it breaks. I tried using the
`--ignoreSheets` command to ignore that stylesheet, but it doesn't do
what I want.

I copied `bootstrap.css` to a simpler place, so the paths were less
messy. I left bower installing to default bower_components so we have
less stuff in the repo.

### Also:

```shell
$ du -hs doorservice/static/css/bootstrap.css
136K	doorservice/static/css/bootstrap.css
$ du -hs doorservice/static/css/doorservice.uncss.css
 12K	doorservice/static/css/doorservice.uncss.css
```