Add Dockerfile

This adds a Dockerfile to run the project. All you need to do now is run
`make` in the root folder and the pdf will be built.

book/latexmkrc

@@ -1,5 +0,0 @@
-END{
-# system("tex4ebook -j output -m draft -a debug main > tex4ebook.log");
-system("tex4ebook -j output -e build.mk4 main");
-system("rm tikz-cache/*");
-}