* Add Nick Schrock testimonial and subtitles to wall of love
- Add Nick Schrock (@schrockn, Dagster Labs founder, GraphQL co-creator) testimonial
- Add subtitle field for notable contributors (Mitchell Hashimoto, Nick Schrock)
- Render subtitle in TestimonialCard between name and handle
* Add Nick Schrock profile photo
* Download avatar images to repo instead of hotlinking
* Show subtitle after name in attribution lines
