eventually-postgres: move outside this repository

[ar3s3ru]

Now that eventually has been moved into an organization, we can detach eventually-postgres completely from this repository and into its own repository.

[danieleades]

i've been thinking about this... what's the advantage of moving it into a separate repo, rather than a workspace? I can think of one potential disadvantage, which is that it's harder to catch and respond to changes in the API