Make ItemStackComparators cataloged type

[XakepSDK]

Make ItemStackComparators cataloged type, so devs don't need to implement their own workaround for CommpandSpec and config serialization.

[ST-DDT]

When would you define/select an itemstack comparator via command/config?

[XakepSDK]

I'm doing plugin, it's logic depends on ItemStack comparison results, i want to give admin more control over how comparison is done. Benefits:

1. Admin controls how ItemStacks are compared
2. Admin can add his own ItemStack comparators by writing a plugin

[ST-DDT]

Sounds like an exotic usecase to me. But it probably wont hurt either.