Add block break actions

[haykam821]

This pull request adds block break actions, which can be used to customize the behavior of breaking blocks. Actions can affect the player that broke the block, all players, or all players except the player that broke the block.

Block break actions can be used to implement additional versions of spleef, such as a version that restocks projectiles when blocks are broken as opposed to on a timer.

For an example of block break action configuration:

{
	"block_break_actions": {
		"minecraft:snow_block": {
			"type": "spleef:sequence",
			"actions": [
				{
					"type": "spleef:add_status_effect",
					"effect": {
						"Id": 1,
						"Duration": 200
					},
					"target": "others"
				},
				{
					"type": "spleef:give_item_stack",
					"stack": {
						"id": "minecraft:tnt",
						"Count": 1
					},
					"target": "all"
				},
				{
					"type": "spleef:restock_projectile",
					"target": "all"
				},
				{
					"type": "spleef:send_message",
					"message": "Example message",
					"overlay": false,
					"target": "self",
				}
			]
		}
	}
}

The block action system is extensible and can be extended later to allow configuration in other contexts or additional actions, such as a generic action to run command functions.