Toggles for item destruction from explosions

**Is your feature request related to a problem? Please describe.**
Explosions (such as from creepers) can destroy loose items on the ground. This could be considered mob griefing, especially if the items were dropped by a dead player.

**Describe the solution you'd like**
A toggle for item destruction for mob explosions and TNT explosions.

**Describe alternatives you've considered**
It could be tied to the block griefing toggles instead of adding new ones, although that's less flexible.