* convert all theme files to json
* automatically discover extra themes in go backend
* use zod
* error tidy up
* error tidy up p2
* generate theme json schema from zod
* generate theme list at build time, don't do it at runtime
* make name and id required in the theme schema
* add basic theme-playground page
* basic theme playground
* generate schema
* sort of include the schema
* proper json schema
* add base theme
* bit of tidy up
* don't use appEvents.emit
* tidy up ThemeDemo
* extract translations
* add CODEOWNERS
* refactor(frontend): rename all @grafana/data/src imports to @grafana/data
* feat(grafana-data): introduce internal entrypoint for sharing code only with grafana
* feat(grafana-data): add test entrypoint for data test utils usage in core
* refactor(frontend): update import paths to use grafana/data exports entrypoints
* docs(grafana-data): update comment in internal/index.ts
* refactor(frontend): prefer public namespaced exports over re-exporting via internal
* chore(frontend): fix a couple more weird paths that typescript complains about
* refactor(frontend): rename all @grafana/data/src imports to @grafana/data
* feat(grafana-data): introduce internal entrypoint for sharing code only with grafana
* feat(grafana-data): add test entrypoint for data test utils usage in core
* refactor(frontend): update import paths to use grafana/data exports entrypoints
* docs(grafana-data): update comment in internal/index.ts
* refactor(frontend): prefer public namespaced exports over re-exporting via internal