Default: Destroy flammable items when in fire or lava

The check for igniters (fire/lava) will be performed every 10 secs
if the item is flammable.

if the item is found to be in lava it will then burn up and
disappear in a smoke puff.

If a non-lava igniter node is found, a combination of `flammable`
value of the item and `igniter` group value of the node will be used
to determine the chance for the item to be removed.