fix: update_positions is not a rest action so it should not call load_resource

Fixes #2627
Fix percent per item calculator to work when no rules restricting products.

Fixes #2660
Fix issue with count_on_hand attribute in sample loading (#2631)
Update activemerchant to requiring at least 1.31.x

Fixes #2661
Factor product scopes to allow simple scopes to be addet from an extension