Add images to third width link blobs

[keelerr]

Just like there are 50/50s (with images) and half width link blobs (no images), it would be great to have a way to add visuals to the third width link blobs.

Rationale
Sometimes you need to feature three things, not two. And, since we're already using third width link blobs, it seems like not too much of a leap to add images to them. As we create more consumer facing pages in wagtail, it's helpful to have a little more flexibility in including imagery. It is technically possible to include an image in there now, but it scales poorly.

@Dnpizarro and @Scotchester we've spoken about this. Anything to add?

[Scotchester]

The only thing I have to add is that adding this would make it possible to dramatically simplify our roster of these kinds of components from:

1. Image and Text 50/50
2. Half-width Link Blob
3. Third-width Link Blob

to a single Info Unit Group module with a simple layout selector with the following options:

• 50/50
• 33/33/33

Image and Text 25/75 would unfortunately probably have to remain on its own, as it requires the image to be present, and it would be difficult to dynamically have the image be required or not depending on which layout is selected.

[keelerr]

UXers discussed this at the bi-weekly. In general, we're onboard. We like the idea of adding more flexibility, and as @jordanafyne pointed out, this type of module would also be helpful on the About us page migration. As for guidance on how people should use this going forward, we could use content strategy/guidelines for 50/50s.

We didn't come up with any drawbacks to this approach. Obviously, we want to create well thought out pages, but it's hard to place specific restrictions on the use of any one module that will automatically lead to the creation of successful, well thought out pages. New use cases that crop up and expand our notion of how/when something should be used. (In short, I'm saying we'll try not to abuse a 33/33/33.)

ETA: More notes from our meeting. Couldn't talk and type at the same time!

[Scotchester]

Onboard with the consolidation plan that I suggested?

[schaferjh]

yup