[NodeJS] Add grid ImageSet style

[paulcam206]

Adding a new ImageSet style to allow for a cleaner presentation. Also improve default ImageSet rendering.

Old ImageSet render (default style)

New ImageSet render (default style)

(a small tweak -- just added vertical padding)

New ImageSet grid style

Schema

{
  "type": "ImageSet",
  "style": "grid",
  "images": [ ]
}

Screenshots

Small

Medium

Large

Large (rtl)

[jwoo-msft]

@paulcam206, Do you think we need to create a tag for new features to be attached to the commit, so that we can easily pull those features when we want to bring each platform to parity?

[paulcam206]

@paulcam206, Do you think we need to create a tag for new features to be attached to the commit, so that we can easily pull those features when we want to bring each platform to parity?

good idea, I created the NodeJS-2403 label to track.