Update documentation

Created by: slifty

This PR adds a new README file while also keeping the original.

It also moves the api into a new services directory. I admit this was first done because I thought that the node and python code were two different services with an organic file structure and could use a refactor. I later realized that the node code really is just a subscript of the python worker and made sense in the api directory.

That said, I also think that services provides some clarity about the nature of the api code -- that it contains code for a separate service which SimpleBook relies on. We may want to consider pulling it into a separate repository at some point (e.g. simplebook-api).

Resolves #5 (closed)