Ensure SSP diagrams are legible and understandable

[mogul]

In order to ensure our new code-driven diagrams are properly understood by JAB technical reviewers, we want to ensure they appear in a legible and easy-to-understand form in the SSP.

Acceptance Criteria

• [x] Exported PNGs are as legible offline as they are on diagrams.fr.cloud.gov
• [x] Boundaries are clearly visible against the background
• [x] Fix arrow in 10-1: AWS console should be bidirectional with Cloud Operations
• [x] Fix arrow in 10-1: Reverse Cloudability/API arrow
• [x] Fix 10-4.1, which appears to not be rendering correctly
• [x] Fix 10-4.3 layout to have fewer overlapping arrows
• [ ] Meet 508 compliance needs 👀 18F/cg-diagrams#10

Implementation Sketch

• Get the source out of Adam's hands so other people can update the source if needed
• Adjust CSS to ensure borders and background show up well, particularly when printed 18F/cg-diagrams#12
• Fix PNG export if possible 18F/cg-diagrams#12

[rogeruiz]

Once 18F/cg-diagrams#12 lands on master, the following issue should be addressed.

• Exported PNGs are as legible offline as they are on diagrams.fr.cloud.gov
• Boundaries are clearly visible against the background

[rogeruiz]

I believe that following item is being addressed by splitting up the diagrams even further and linking between them. Is that right, @afeld?

• Fix 10-4.3 layout to have fewer overlapping arrows

[afeld]

Yep! Moved to https://github.com/18F/cg-diagrams/issues/13.

[mogul]

(Please reference this issue in other issues and PRs so they'll show up here.)

[afeld]

Left some open issues in https://github.com/18F/cg-diagrams/issues, but I think we can call this "good enough for now".