* Add mergify config
This config includes the following rules:
- Automatically merge once a PR passes all tests and is approved.
- Automatically backport each PR from our main branch into our stable branch
* Merge all tests into one run
* Cleanup and speed up test suite
* Migrate to a docker image with dav1d
* Create CI profile with debug assertions enabled
* Use faster params for all encoders
Co-authored-by: Redzic <yusufredzic@gmail.com>
