Libkiwix CI should use zim-testing-suite

[kelson42]

This would simply allow a better/simpler testing to use directly https://github.com/openzim/zim-testing-suite in place of "reinventing the wheel" here.

[stale]

This issue has been automatically marked as stale because it has not had recent activity. It will be now be reviewed manually. Thank you for your contributions.