Remove remaining traces of Postgres

[grahamalama]

Checklist:

Before submitting your PR, please confirm that you have done the following:

• I have opened my PR against the staging branch, NOT against main
• I've run the relevant formatting and linting tools listed in the setup docs
• I have commented hard-to-understand areas in my code
• I've reviewed any merge conflicts to make sure they are resolved
• My changes generate no new warnings

Description

Since we've moved to Parquet files and are no longer using Postgres, in this PR, we remove the remaining code and documentation referencing Postgres.

I essentially just did a find + replace for postgres, database, pg, etc, so there could very well be some places that I missed. But I think I got most of it.

Type of change

• Bug fix
• New feature
• Breaking change
• Internal change

How Has This Been Tested?

I built the container with

docker compose build --no-cache vacant-lots-proj

then verified that it ran with

docker compose run --rm vacant-lots-proj

the pipeline is currently not working (see this comment), but I took the fact that it starts to run as a sign that things are still working with the code I deleted.

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Name	Status	Preview	Comments	Updated (UTC)
vacant-lots-proj	✅ Ready (Inspect)	Visit Preview	💬 Add feedback	Jun 8, 2025 8:04pm

[nlebovits]

Nice! You might also want to grep for VACANT_LOTS_DB. But otherwise, it looks good to go.

[cfreedman]

Looks good to me too. I'm going to merge this in and then I'll take out the rest of the VACANT_LOTS_DB in #1226 once I do the final rebase to merge it in.