External JSON sync + demo file of hardcoded templates for node types

[jake-figma]

Add a new JSON schema / type like:

type TemplatesByNodeType = { [k in BaseNode["type"]]?: CodegenResult[] }

For folks to hang templates on in the codebase itself and have that be the fallback.

This wouldn't work in the official plugin, but would be useful for folks who clone this and want to add templates for things like Typography and Layout components.

[jake-figma]

Also worth considering hosting the templates externally on an oauth'd account (eg. #22), or even more simply in an externally hosted/public JSON endpoint.

[jake-figma]

first cut playing around with this global templates concept. instead of being hardcoded (templates.ts) this would be loaded from a JSON endpoint. #14412db

[jake-figma]

First draft of this is in with #30

Closing for now, but open to discussion on improvements here (especially loading via JSON). Documentation for Global Templates can be found in the README