Fixes pups' CSS

Pup' CSS was all over the place, this commit gathers all the scattered
pieces and puts them into pups.css
Updates README.md
#12625 Stops prodromus from eating http/https links.

The webchat UI previously ate http/https from links as a form of
simplifying/beautifying urls but that proved bad when users copy/pasted
logs so now it displays full links instead of simpler ones.