Added an on_attack callback that allows to execute additional custom logic after each attack.
Reviewed-on: https://git.minetest.land/MineClone2/MineClone2/pulls/4064
Co-authored-by: the-real-herowl <wiktor_t-i@proton.me>
Co-committed-by: the-real-herowl <wiktor_t-i@proton.me>