Feature: add Postgres target

[morsapaes]

Is your feature request related to a problem? Please describe.

Although Kafka is a great place to start building out the tool, it'd be useful to extend the generator and support producing data to a Postgres target. This would ensure we don't force users to adopt and/or learn Kafka if their use case just requires direct Postgres CDC to Materialize.

I can also see this being useful for internal testing of our Postgres source.

Describe the solution you'd like

Since we already support .sql files as input, we could run these against the specified connection to bootstrap the target database (+ which should be configured for logical replication). Generating relational data sounds a bit tricky, but there are a few SQL Faker implementations out there we could draw inspiration from (e.g. sqlfaker, sql-faker). I'd be motivated to work on a prototype! 🖖