Reorganize ToC

[JoshOrndorff]

Solves #204 #313 #327 and #344. Obviates #316

This PR is a restructure of the recipes to strip out the parts that needed to be read in order and slim the repo down to be more about the working code examples.

The new ToC is as follows:

* Introduction
* Pallets
  * Storage Maps
  * ... lots of pallets elided ...
  * Tightly- and Loosely-Coupled Pallets
* Runtime
  * Runtime APIs
  * Transaction Fees
* Consensus
  * Sha3 PoW Consensus
* Nodes
  * Kitchen Node
  * ... other nodes elided ....
  * Hybrid Consensus Node

Task list:

• [x] Prune setup instructions
• [x] Prune appetizers
• [x] Restructure TOC
• [x] Revise runtime printing recipe
• [ ] Revise event emitting recipe
• [x] Fix tons of broken links

[JoshOrndorff]

Since some reviewers may not know, to see the result of these changes, you can clone and build the book locally:

git checkout joshy-reorganize-toc
mdbook build --open

[wheresaddie]

@danforbes good to note, fyi it's running clean on my chromium locally on a ubuntu box atm

[jimmychu0807]

The ToC looks great and makes recipes get right to the meat. Made a PR #349 for minor enhancement.

This PR is killing a few birds with one stone 😄

[wheresaddie]

yeap looks awesome.. thanks @JoshOrndorff