9648a91a

By: Tom Sydney Kerckhove <syd@cs-syd.eu>

Rename packages to sydtest-sqitch-postgres[-persistent], add plan tests, drop integration flag, copyright

Three concerns landed together because the rename touches everything else:

* Both packages renamed: sydtest-sqitch → sydtest-sqitch-postgres,
  sydtest-sqitch-persistent → sydtest-sqitch-postgres-persistent.
  The "postgres" is in the name now because these packages are
  PostgreSQL-specific (sqitch supports multiple engines) and the
  precedent in this repo is to suffix the engine name.

* Modules renamed in lockstep: Test.Syd.Sqitch → Test.Syd.Sqitch.Postgresql,
  Test.Syd.Sqitch.Persistent → Test.Syd.Sqitch.Postgresql.Persistent.

* The sydtest_integration_tests cabal flag was removed from both
  packages. It was copied from sydtest-persistent-postgresql, where it
  exists to gate the extra Haskell test deps; here the integration
  tests need the sqitch executable at runtime, not as a Haskell dep,
  so the flag was doing nothing useful. Test setup detects the
  executable on PATH with findExecutable and fails the test cleanly
  if it's not there.

* Five more readSqitchPlan unit tests: tag at start, tag at end,
  grandfather tag IS the rework tag, change reworked twice, blank /
  whitespace-only lines.

* LICENSE copyright bumped from 2021 to 2026 in both packages.