Deliverables need per-state content

[ramijames]

I've been thinking about this for weeks and there is no way around it: deliverables need per-state content.

For workflows, you'll need to divide files, links, and content for each state in a workflow because if not there will be no way to:

• go back to a previous version
• reference created content like outlines
• create comment sets on top of previously created content for reviews

To accomplish this, I'll need to create a new table which will house the state_content, and migrate current deliverables to use this.

Currently each deliverable has a set of columns for file, link, and markdown. I'd like to replace this with a reference to the uuid of the state_content row.

In the state_content row I'll need:

• uuid (primary key)
• content (json)
• last_updated (datetime+tz)

For the content json I'd like to have:

• state_instance for each state instance in the current workflow
• content_type for each state_instance
• content for each state_instance

[ramijames]

When you create a deliverable, it should automatically go and create the associated state_content row, and populate the deliverable with the uuid.

[ramijames]

Completed with latest commits 0df8dd5