Sends token & comment when the chat session starts

Sends token and comment of the related ticket to the support assistant
at the start of the chat session without sending them to the user's web
UI.
using .text() instead of .html() to prevent xss attacks
Swapped variables for constants in prodromus.js
using django's slice instead of truncatechars
using <a> instead of <span> for links
using static methods instead of instantiating
removed Token.get_token()
Implements Stats

Stats is a client-side tool that helps support teams report what
kind questions they answer and their frequency.
pups/home now reports personal user stats
added a management page which points to extractReport and wipeStats
Enable monthly on-disk backup stats reports

A user (likely the admin in the future) can now login, visit,
pups/management and save a stats report on disk by month/year. The
saved reports are stored in a path by choice in pups.settings.py's
CONFIG dict which can be modified.
Enabled viewing archived stats reports
pep8 cleaning
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
get_home_stats() now makes uses of the database instead of logic

Previously, get_home_stats() used logic to decide what tokens
are live/expired/revoked or not using a for loop with theree
test cases, this commit fixes that and uses the database instead.
#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.