First draft of the introduction

Rewrote the introduction as a usecase.

Pulled the introduction into a separate file.

This is a first draft but thought I'd get out a general idea of the introduction I had out as soon as possible.
I don't know where the line is with regards to referencing sources when we claim something. So, if it is too much, ignore this comment.

Does a claim of daily use for these purposes need a source? Sure, it is "common" knowledge, so I am not sure.