Separate the schemas for manuals and sections

This will make dropping in the actual schemas easier.
Merge pull request #14 from alphagov/separate_schemas_for_manuals_and_sections

Separate the schemas for manuals and sections
Add examples of JSON

These are the manual and some sections of the scraped Employment Income Manual
from manuals-frontend, modified to fit our initial schema.

- EIM00100.json is the 'About' section, with content in the body and no child sections
- EIM77010.json is an appendix, with more content in the body and no child sections
Remove 'manual' from key names

It seems redundant when you have the context of the format name.
Simplify (shorten) example JSON
Strawman of JSON to send to Content Store
Remove some sections for easier maintenance

We don't really need so many examples, and it was becoming a hassle to tweak
and maintain whilst keeping them consistent.
Move JSON closer to Content Store format

This will simplify the job of translation.
WIP manual schema