* Pass CNode* to IsMasternodeQuorumNode and let it also check verifiedProRegTxHash
This makes IsMasternodeQuorumNode return true on incoming peer connections
as well.
* Let GetMasternodeQuorumNodes also take verifiedProRegTxHash into account
This makes it return NodeIds for incoming peer connections as well.
* Remove AddParticipatingNode and the need for it
This was needed in the past when we were unable to identify incoming
connections from other quorum members. Now that we have MNAUTH, we can
easily identify all connected members.
* Don't track interestedIn quorums in CSigSharesNodeState anymore
Same as with the previous commit, we're now able to easily identify which
nodes to announce sig shares to.
* Remove unused CConnman::GetMasternodeQuorumAddresses
