Feature: PDF book

**Which module(s) and week(s) does this change affect?**
Module(s): all
Week(s): all

**What is the work that needs to be done?**

1. create a layouts/_default/book.html
2. compose all the preps, day plans , guides, etc that we want on to this page
3. write a proper print stylesheet (do this even if not the pdf part)
4. consider: generating a pandoc pdf after build or throw in a jsPDF and put the book in the Guides menu

**Why is this work important to do?**

We want to make this site as usable as possible and properly thought out printable pdfs is part of that

**Additional context**

I'll probably do this, just writing it down so I don't forget, but feel free to scalp me 😉 just make sure you update the ticket

**Who might need to know about this change?**