Reduce schema.sql

[Changaco]

First step of #2360, and #1549.

[seanlinsley]

Did you perform this change manually? Perhaps schema.sql should be automatically generated from a schema dump from the database.

[Changaco]

Yes, I did it manually, the output of pg_dump -sO was unsatisfactory.

[seanlinsley]

Surely manual updates will become unmaintainable going forward. Perhaps there's a tool we can use to generate good-looking schema dumps?

[Changaco]

I diffed the results of pg_dump -sO on a backup of the production DB and on my local test DB created with the new schema (using make test-schema). Found a few mistakes and a missing index.

[Changaco]

Okay, the build is fixed, this is ready for merge. There is little risk in merging since schema.sql is obviously never run on the production DB.

[Changaco]

Merging so that I can move forward with PRs that have a branch.sql without risking conflicts.