feat(registry): deis-cache for saving meta data

This improves the registry speed with remote stores and improves the developer UX

Fixes #1780, fixes #1794
> Redis doesn't listen to SIGHUP (thats why there is no reload cmd)

If Redis doesn't listen to SIGHUP, then how is it going to reload when something changes in the config file from etcd? That defeats the entire purpose of using confd for dynamic config :(

PR 85 would definitely help in the performance department. I'm just not sure that confd is necessary in this case.