Implement locktower voting (#3251)

* locktower components and tests

* integrate locktower into replay stage

* track locktower duration

* make sure threshold is checked after simulating the vote

* check vote lockouts using the VoteState program

* duplicate vote test

* epoch stakes

* disable impossible to verify tests

core/src/lib.rs

@@ -42,6 +42,7 @@ pub mod leader_schedule;
 pub mod leader_schedule_utils;
 pub mod local_cluster;
 pub mod local_vote_signer_service;
+pub mod locktower;
 pub mod packet;
 pub mod poh;
 pub mod poh_recorder;