Deletion of deal rendering module, replacing with example

[patmmccann]

pbjs.onEvent('bidResponse', (bid) => { if (bid.dealId /* or any other condition */) { bid.renderer = { renderNow: true, render(bid, doc) { // do your own rendering doc.body.innerHTML = bid.ad; } } } })

We have a module, the MASS module, that allows publishers to apply renderers to display deals. The above code snippet does the same thing. As MASS has been acquired and the module is scheduled for removal, we'd like to add this code snippet but not sure where. The multiformat page actually seems to have no discussion of renderers

[bretg]

@patmmccann - opened #4642 as the easy thing here.

Will need someone else to refactor the rendering documentation. I don't think that's a requirement for merging the PBJS 8 docs, but we can leave this item open until done.