[dashpay/dash] [WIP] DIP2/DIP3/DIP4 Implementation (#2083)

re regtes sync: the difference is that with https://github.com/UdjinM6/dash/commit/b8c0f425bbcecb95c0ee2df1345298364faef163 it actually does smth 😛`force_finish_*` just skips all the logic and no messages are sent.