Embed Postgres with OpenGB CLI to remove Docker dependency

[NathanFlurry]

See:

• https://github.com/faokunega/pg-embed
• https://github.com/zonkyio/embedded-postgres-binaries
• https://github.com/opentable/otj-pg-embedded
• https://github.com/electric-sql/pglite

Easiest path is likely to use the Rust library to create a Deno plugin.

Before embarking on this, ensure that

• This solution is portable
• Supports the same extensions that's available on Neon
• Still supports a Docker fallback