User story: As a facilitator or communications person, the interface to modify text and image content should be technologically straightforward.

• Problem: Currently, strings are implicitly joined, multiline strings in messages.py. But not all strings are located there, some are hard coded in the HTML (headings, form labels). These are harder to maintain than necessary.

Proposed Solution

• Move all content strings into a YAML file. This provides a clean interface for modifying text content.
• Move all image paths into the same YAML file. This provides a clean interface for modifying image content.
• Modify HTML to use Jinja2 templates to reference the YAML file. https://flask.palletsprojects.com/en/stable/templating/