Putting in content

#### What's the plan?
To add the initial milestone copy so we can see it with the real copy, and to play around with how that copy looks.

#### What's this PR do?
Adds in the copy that we have for the first themed content area. Adds in the other headers that are defined in Basecamp, as well as more specific placeholder images with labels for what they placehold. Makes elements mobile friendly in a way that should hopefully facilitate easy switching out of placehold content for real content.

#### How should this be manually tested?
Fire it up locally and check out how the real copy looks in the first section, and then how the rest of the headers and placeholders look in the other sections.

#### What are the relevant tickets?
Part of FMD iteration Sprint task: https://basecamp.com/1866004/projects/1175549/todos/124146976

#### Next steps?
Keep adding in copy/content, seeing how it looks, and iterating on those styles...

#### Smells?

#### TODOs:

#### Has the relevant documentation/wiki been updated?

#### Technical debt note