Firebird-qa

Added

- Fixture `existing_db_factory` to directly use database from `databases` subdirectory.
It's not intended for use in Firebird QA, but it's necessary for other plugin
users.

Fixed

- Report test error also in cases when unexpected stderr is returned from tool execution
while `returncode` is zero.
- Select test marked for current platform also when it's not marked for Firebird version.

Fixed

- Problem with ndiff in assert

Fixed

- Remove fix for 21. The error was not caused by pytest 8.0, but by `Error` exception from
`firebird-base` package that masked the absence of `__notes__` attribute from `pytest`.
Dependency to pytest reverted to `>=7.4`.

Changed

- Updated documentation.

Fixed

- Fix for 21. Dependency to pytest changed from `>=8.0.0` to `~=7.4`. Other dependecies
changed from `>=` to `~=`.

Changed

- Switch from `setuptools` to `hatch`.
- Updated dependencies.

Added

- Added cache for empty databases. This works transparently and does not require any
special configuration. Databases are stored in `dbcache` subdirectory (created automatically)
for combination of ODS + page size + SQL dialect + character set.

Files in `dbcache` directory could be removed as needed (including whole directory)
to fore creation of new database.

Cache is enabled by default. Use new --disable-db-cache option to disable it.