Style Modes

[JaceHensley]

closes #2

[JaceHensley]

Open to suggestions on better structuring of the schema

How I'd write the TS types:

type Image = {
  uri: string
  alt: string
}

type Color = {
  color: string
}

type BaseESD = {
  thumbnail: Image
  hero: Image
  background: Color
  text: Color
}

type StyleMode = {
  mode: string
  styles: BaseESD
}

type BasicESD = BaseESD & {
  style_mode: StyleMode
}

type ThemedESD = {
  light: BasicESD
  dark: BasicESD
}

type ESD = BasicESD | ThemedESD