feat/cyanea

[Arc-blroth]

• upgrade yarn -> v4.0.2
• Migrate to our new shiny Cyanea events!

One of the last steps in my winter-long project to automate basically all of marketing:tm:!

This PR replaces and deduplicates the original event/archive system with a single source of truth in data/events.json.

It also fixes a couple of bugs and limitations with the original event system:

• Events now get automatically moved to the archive based on their timestamp (sorry Audrey)
• Events now have both a start and end time, and can theoretically last for multiple days
• Events can now be tagged with multiple Cyber "series"/tracks/things
• the components on the Events and Archive pages are now actual React components, with proper keys
• the alt text for event banners is no longer "Placeholder Image" 🧌
• #bringbackspecialtopics

There's actually a couple of typos in the events.json currently supplied ("Polygots") for both recent and historical events.
I plan to fix those typos as a demostration in the first real Cyanea sync - coming soon!

[bliutech]

Really cool! Great work. LGTM.