Migrate from Grunt to npm for squoosh (#479)
This made the work a bit complex:
https://github.com/imagemin/imagemin/issues/191
And https://github.com/imagemin/imagemin/issues/385 recently painted the way to Squoosh instead.
Co-authored-by: Volker E <Volker-E@users.noreply.github.com>
Bug: T246321