Add ClipSet to schema

[adgad]

There was an initial attempt, that was paused with a view to making things more consistent across the nodes.

I think something like this would be consistent with the rest of things (commented where I've made some field name changes).

Note: this will require changes in Spark (toContentTree/preview) and cp-content-pipeline, to align with the changes.

ClipSet

interface ClipSet extends Node {
  type: "clip-set"
  id: string
  autoplay: boolean
  loop: boolean
  muted: boolean
  layoutWidth: 'in-line' | 'mid-grid' | 'full-grid' //renamed for consistency note: does spark only support these? as opposed to the full set of layout widths other components support? if so, why?
  external noAudio: boolean
  external caption: string
  external credits: string
  external description: string
  external displayTitle: string
  external subtitle: string
  external clips: Clip[]
}

type Clip {
  id: string
  format: 'standard-inline' | 'mobile'
  sourceSet: ClipSource[] //renamed for consistency
  poster: string
}

type ClipSource {
  audioCodec: string
  binaryUrl: string
  duration: number
  mediaType: string
  pixelHeight: number
  pixelWidth: number
  videoCodec: string
}

ClipSet represents a short piece of possibly-looping video content for an article.

[adgad]

Discussed IRL:

• layoutWidth is fine, check Spark to confirm those are the only three options
• Nested bodies: ideally, we'd keep Body as the type in content-tree, and make the GraphQL API coerce it's response to match. See if that's possible...
• We think it's fine to add Text as an allowed child of Body