#experiments.md - create experiment button display grid

[kgrons]

Current: each experiment is linked via a button on its own line in experiments.md

Desired: Experiment buttons are in a grid (or more intentional) layout

• Inspiration from Chrome Music Lab where buttons are engaging/inviting and hint to what the experiment examines or achieves.

Current challenges are our own limited understanding of how GH-flavored Markdown is rendered in GH pages/Cayman blog theme applied.