Implement VRT for website

[alisonjoseph]

Baseline VRT

• Homepage ("Latest news and articles" section pulls from medium)
• Most visited "Guidelines" page
• guidelines/icons/library (notorious for breaking)
• guidelines/pictograms/library (notorious for breaking)
• guidelines/typography/type-sets
• Most visited "Components" page (usage and accessibility tabs)
• Most visited "Patterns" page
• Data viz -> simple charts
• Contributing page (since this pulls from airtable)

Only ~10 snapshots per PR build and would give us reasonable assurance we didn't totally break anything

[tay1orjones]

Since we reduced Percy usage by ~50% in carbon-design-system/carbon#14779, I think we could do this but we'd need to be mindful of our quota.

[tay1orjones]

Instead of using playwright for taking and sending the percy snapshots, we could just invoke the percy cli and keep the usage as dead-simple as possible.