Implement recommendation highlight

[edwindotcom]

This ticket should replace one of the tiles in the Highlights section with a "recommended" tile, if possible.

We should be able to use the new pocket recommendation engine to do this.

[Edit by @k88hudson for clarity]

spec:
https://trello.com/c/TQcZZhMe

[k88hudson]

We still need to work out:

• What should be the source of the recommendation? Should it be related to an existing tile that is also shown? Should it replace the tile it is related to? Should it be a general "trending" recommendation?
• What if a recommendation is not available from the designated source? Should we replace it with a general recommendation? Should we just not show it?
• How frequently should recommendations be shown? All the time when we have one? Only sometimes?

Also note: we should try running this as an experiment.

If you want, I can try something like replacing one of the tiles with its recommendation, and we can look at it/go from there

cc @bryanbell @aaronrbenson

[k88hudson]

If you want, I can try something like replacing one of the tiles with its recommendation, and we can see how that goes.

[k88hudson]

Note: this is also blocked on implementing pocket endpoints in the proxy

mozilla/embedly-proxy#122

[aaronrbenson]

[k88hudson]

@tspurway I wasnt able to make the meeting on Thursday, did you end up asking about the short URLs?

[k88hudson]

Also thanks for the clarification @aaronrbenson! Looks great

[sarracini]

Fixed with #906