chore(apollo): make previous Apollo Link change breaking

[jtoar]

This is a follow up to #8500.

When I was trying to release that PR, I had a discussion with @thedavidprice about the name of the prop, linkFactory. After coming up with a few names, we decided to just break link instead. The reasons were...

• the major is coming up
  • if the major was very far away, we probably wouldn't break it, but the RC is more-or-less imminent
• the users of link aren't many (just my guess), and of those who use it, they'd probably prefer this API to the previous one, which was cumbersome

This PR also includes several stylistic changes to the web/src/apollo/index.tsx file, mainly around comments (changing some /** ... */ comments to //), and around the name of types, preferring longer but more descriptive types.