Split mobGriefing into hostileMobGriefing and passiveMobGriefing

When it comes to mobGriefing I would love to play with it enabled sometimes to ensure my builds don't get destroyed. However, I tend to keep it disabled due to the way it interacts with villagers. This is a weird interaction when it comes to a gamerule. Other gamerules like doFireTick, and keepInventory are very straightforward and the only decision the player has to make when changing them is whether to turn them on or off. With mobGriefing players are choosing between Creeper holes and dynamic villagers, so no matter what you pick there is still a downside.