Release lattice/CRDT crate in its own repo

[jhellerstein]

Requires docs. Lead with CRDT for marketing, and in the spirit of VLDB "Keep CALM" paper, route people to Hydro as "fixing" the problems of CRDTs in a principled way.

We should think of this as a disciplined marketing exercise -- that is, we should release this only when we're ready to "route" or "migrate" the users toward Hydroflow.