Experiment with the Dashboard V2 schema

[K-Phoen]

Can be found in grafana/grafana: https://github.com/grafana/grafana/blob/main/packages/grafana-schema/src/schema/dashboard/v2alpha0/dashboard.schema.cue

Validate that:

• cog can parse it
• cog generates valid code from it (types, builders, converters)
  • in TS
  • in Go
  • in PHP
  • in Java
• we can use compiler passes/veneers to generate good builders from it