* change satellite.Peer name to Core
* change to Core in testplanet
* missed a few places
* keep shared stuff in peer.go to stay consistent with storj/docs
we've decided to rename design docs to blueprints to indicate that we don't intend to keep blueprints up to date once completed. instead, the final step of blueprint implementation is to archive the blueprint and update actual documentation elsewhere (potentially copying and pasting most of the blueprint). this PR updates the template and readme