Carpet LAB Addition

Carpet features created for the LAB SMP, as we need them. Currently only contains features for Scarpet.

Scarpet events:

`__on_player_message_broadcast(player, message)` - Triggers right before a player message is broadcast to the server. - Can be cancelled by returning 'cancel', which prevents the message from being sent. - Useful for making changes to chats before they're sent.

`__on_player_edits_sign(player, block)` - Fires after a player edits a sign, after the vanilla text changes take place. - Can be used to add custom sign formatting. - Example script

Scarpet functions:

`encode_snbt(expr, force?)` - Essentially the same as `encode_nbt(expr, force?)`, except it allows heterogeneous lists - This is done to bring it in line with vanilla's new NBT format