Update project section to include create from template

Tells the user how to create a new draft project using a project
template.
Add Project template section

Features for CRUD'ing project templates via the API was recently
added. This is the documentation for these features. Note that
RUD all are done via "projects" in the UI so I kept that behavior
and note that in the API documentation.
Document how to publish a draft project

POST to the projects/:id/publish route to change a draft project
from draft to published.
Update attributes returned in projects GET

Template true/false is now returned with the changes that add
project templates to the API
Update json responses from project API

If out of projects API now response with 507 Insufficient Storage
and not 403 Forbidden. Unauthorized users still get the 403 response.
Update copy dealing with draft projects

This clarifies what a draft project is and how to publish it. Combines
the two sets of documentation to make expected behavior more clear.
Merge branch 'update-documentation-to-include-project-templates'