document knowledge base development process for CEDAR message templates

[zachll]

Problem: It is not clear how we create message templates using forms in CEDAR

• describe the standard process for creating a new message template
• describe known issues that have occurred and how to get around them -- the @value issue -- the way that the "is about" table is finicky

Edit this document: https://docs.google.com/document/d/1xxcZJ2yPpBTxW-udzQGQH8_j3ClAO1hio4tSjpYLGjI/edit