HIP-17 : Remove Blacklist from the protocol

[johnashu]

Summary : This proposal is to remove the blacklist

Background : After opening this proposal we found out that only the leader need to update the already existing blacklist.

I just got word from @rlan35 that this list needs to be only updated on the leader, so 4 nodes that are currently managed by Harmony.

Motivation : Every Validator who set up a node is probably aware of ./hmy/blacklist.txt
By open our network to 100% external Validator and also external leader we are facing the extrem high risk of misuse the blacklist system and we have no more controll over it.

Specification : Blacklist needs to be removed from the protocol