Add support for content collections injection

[BryceRussell]

Currently, if a theme uses a Content Collection, the theme user has to either clone a template with the Content Collection or manually set it up inside their own project. It would be nice if themes had the ability to automatically inject Content Collections into a project. This could be accomplished using a library like ts-morph to read the content/config.ts file and inject a schema into the collections object

Goals:

• Automatically generate and seed content collections
• Automatically inject collection schemas into user's projects

Things to consider:

• AIK uses recast for codegen, should this be done using ts-morph or recast?
• Should this be a separate package, so others can use it too?
• Should the codegen happen directly on the file or inside a Vite plugin behind the scenes, meaning a user will not be able to see the schema inside the config file?

Working prototype using ts-morph: https://github.com/BryceRussell/prototype-inject-collection

[Fryuni]

// Without any extra config
export const idea7 = {
  docs: defineCollection({

  }),
}

// With some config to disable the auto-injection
export const idea7a = {
  darculaColors: darculaColorCollection({

  }),
  docs: defineCollection({

  }),
}

Might come from Fryuni/inox-tools#82 before you notice it