Create context starter templates
## Problem/motivation
Follow up to:
#3586170
This issue could be repurposed as a discussion or design/UX issue.
Provide starter templates for more common types of context that users can select from, e.g. brand guidelines, tone and voice, editorial standards. These can have a recommended structure with important headings and instructions in each heading, and example context items with everything filled in.
## Solution
TBD
## Tasks
- Discuss
- Design/UX
- Architecture
- Implementation
- Review and test
issue