Move documentation from e-c-addon-docs to field-guide

[elwayman02]

e-c-addon-docs is more or less unmaintained, so let's move our docs to the future and use field-guide instead. Here's an example of a similar addon that uses field-guide:

https://github.com/elwayman02/ember-resize-modifier/tree/master/docs

Setup should be fairly simple - Copy the markdown files from e-c-addon-docs to the location field-guide expects them to be and delete any e-c-addon-docs code from the demo app.

[garrettwelson]

Hello! I'm definitely interested in taking this on. I've used the addon a fair amount and love working with it

[elwayman02]

One interesting part of this project will be migrating the living demo. Thankfully, the example I linked above shows how field-guide supports creating component classes to back the demo code in the markdown files. You can find that file here: https://github.com/elwayman02/ember-resize-modifier/blob/master/docs/modifiers/did-resize.js

[elwayman02]

Fixed!