Allow selective disabling of rules per query

[rhodeon]

This resolves #3619 and has some minor refactor in regards to reusable constants.

As mentioned there, the @sqlc-vet-disable query annotation now accepts a list of rules to skip:

/* @sqlc-vet-disable sqlc/db-prepare no-pg */

Providing just /* @sqlc-vet-disable */ without any parameters retains the previous behaviour of skipping all rules for a query.

[rhodeon]

@kyleconroy, can you please confirm if this is something worth having? We have quite a few queries which benefit from it.

[rhodeon]

Hey, @kyleconroy. 🫡 I noticed you made a push for this about a week ago. Is there something else I need to do for it to be merged into main?

[kyleconroy]

@rhodeon thanks for the updated push. The docs and tests are great! This will go out with the next release.