* feat: password reset via symfonycasts/reset-password-bundle (#179)
Implements the full password reset flow using the SymfonyCasts reset-password-bundle.
* ci: share base layer cache between dev and prod builds
* fix: use CSS form selector in tests instead of translated button text
* fix: translate missing validator string for reset password email field
* fix: translate reset password form labels via TranslatorInterface
* ci: override MAILER_DSN to null for PHPUnit so mailer host is not required
