CCBUG:341752 Make it possible to reload presets that come from a bundle

The KisPaintopPreset::load() method broke when trying to reload a preset
that's in a bundle, and that method is called whenever we activate a
preset unless dirty presets is on.

It's probably worth thinking whether it's a good idea to hit the disk
on every preset change...

Note: this makes krita/image depend on kostore, which is in koodf. Which
is not ideal.