Design: Add more visuals to get.gov pages

[kristinacyin]

Issue description

We have a really strong brand presence in the home page with the help of illustrations but that is lost amidst the rest of the site. There are also concepts that could be helpful to visualize (ex. registrar vs registry).

Quotes from Slack thread:

I think we have such a strong brand presence on our home page with the aid of illustrations but we kind of lose that amongst the rest of the site. -Gaby

Now I'm dreaming of a future where we add some illustrations to visualize these concepts (registry, registrar). But I'm just a visual learner... -Gaby

Acceptance criteria

• Identify pages that would benefit most from illustrations, images and animations.
• Sketch out visual concepts
• Create visual assets, making sure to keep it consistent with branding
• Add visuals to webpages

Additional context

FYI - RSVP'd by @kristinacyin and @gabydisarli

Links to other issues

No response

[vickyszuchin]

Refinement tag added: per Product (Cameron), this ticket requires further refinement, to expand the focus from just illustrations to visuals (e.g., image, screenshots, animation). cc: @kristinacyin @Katherine-Osos