Pytest-qaseio

- Use updated `qaseio` sdk (^4.0.0)
- Rework getting browser name (see `README.md`)
- Drop `Python 3.10` support
- Drop `pytest-variables` support (now use pytest options to provide browser name)
- Add `ruff` and `cspell` linters
- Small code and structure improvements

- Fix `filelock` blocking for parallel tests run

- The remote browser name is now also looked up in the `stash` attribute
in `pytest.Config` to add support for ^3.0.0 versions of `pytest-variables`

- Refactor the use of `pytest-variables` in `QasePlugin`
- Added description of pytest options to docs

- Initial release