Blueprint for memcached

[aarcro]

Looks like the elasticache package only supports redis

[phobologic]

Thanks @aarcro - at some point we'd love to build one, but we actually never even got around to using the elasticache for redis that I built here, due to changes in a design here at Remind. Hoping I'll get a chance to get back to this soon and dust it off - I'm sure that this design isn't quite perfect.

PRs welcome!