Get off of slonik fork

[lognaturel]

We are currently using a fork of slonik: https://github.com/alxndrsn/slonik/commit/b0299faa6405e474ea84d6c96dffecc98001a6e2

This is because of some stream-related issues.

At least one related patch has been accepted to upstream node-postgres: https://github.com/brianc/node-postgres/pull/2836

History of postgres clients used in Central:

• Started out with knex: chaining based query builder but wasn’t great to work with
  • Streaming-related bugs
• Swapped to slonik because it seemed closer to desired interface
  • Tests ran 30% slower than knex (not clear on production impact)
  • Experienced several streaming-related bugs
  • Single maintainer has come and gone in availability
• July 2022, started considering postgres.js
  • Lots of energy behind it
  • Uses a similar tag template literal interface as Slonik
  • issa discovered after finished Slonik work
  • Would have switched to it, but at the time, it didn’t support composing SQL fragments ("partials"), now introduced
  • Transactions weren't initially working, at least in tests
  • Initial PR: https://github.com/getodk/central-backend/pull/564
  • Lots of tiny differences from Slonik. For the most part, it’s an improvement. A lot of things that we did by hand before, porsager postgres has an answer.
  • porsager postgres has some weird quirks of its own though, e.g., no join utilities.
  • So far it’s a code reduction. No queries so far have needed to change. Only core infrastructure has changed so far.
  • Streaming issues - https://github.com/porsager/postgres/issues/455; would need to add support for multiple streams

A barrier to upgrading slonik has been several breaking changes since the version we were on. It seems there's likely a more deliberate approach to breaking changes now: https://github.com/gajus/slonik/issues/450#issuecomment-1409464447

There is now a bridge to use slonik on top of postgres.js instead of node-postgres: https://github.com/gajus/postgres-bridge