Use Docker Secrets in dev and production

[humphd]

This is part of #43. I need to be able to set all the Docker Secrets for the container. In development, we can create any secrets we want in dev-secrets/*. The filename is the name of the secret, and the contents of the file is its value.

I've rewritten the code to use a new ~lib/secrets.server module, which does the right thing in dev and production.

We probably need to move more things out of env and into secrets, so help me find them.

NOTE: the database URL has to be in both places, due to how Prisma works with the command line tooling.

[shawnyu5]

Does our E2E tests need to be modified as well?

[humphd]

Does our E2E tests need to be modified as well?

yeah, just debugging that now. There are 2 issues: 1) we can't use NODE_ENV=production here; 2) we're running from within ./build in e2e tests, so I need to get the path levels right for loading the secrets, or copy them over into the build dir.

Still trying to get it right.

[humphd]

I've updated this so it passes tests. It wasn't easy to figure out the right way to do it, but I think I've got a solid solution now that works in all the various ways we run the code (bundled vs. unbundled, vitest vs. e2e vs. dev vs. stand-alone). Let me know if any of this doesn't make sense.

[Genne23v]

It looks good to me

[humphd]

I'm going to land this, but fyi @dadolhay and @sfrunza13, this will affect you both in PRs you have open now.