Jason Plum authored Sep 15, 2023 and Dustin Collins committed Oct 10, 2023

Add support for explicitly bypassing schema post-migrations to
`wait-for-deps` scripting that detects the codebase version.

Add `BYPASS_POST_DEPLOYMENT`, that will cause the use of checking
`db/migrate` when present. This is in place of `db/schema_migrations`
as `db/migrate` will only have pre-migrations that are required for
the application to start.

Supplemental: large cleanup of outdated code, from prior to 16.0
- We no longer support `schema.rb`
- We no longer use Rake tasks
- We no longer read `structure.sql` (as `db/schema_migrations` or
  `db/migrate` will always exist)