* Added LeaderScheduler module and tests
* plumbing for LeaderScheduler in Fullnode + tests. Add vote processing for active set to ReplicateStage and WriteStage
* Add LeaderScheduler plumbing for Tvu, window, and tests
* Fix bank and switch tests to use new LeaderScheduler
* move leader rotation check from window service to replicate stage
* Add replicate_stage leader rotation exit test
* removed leader scheduler from the window service and associated modules/tests
* Corrected is_leader calculation in repair() function in window.rs
* Integrate LeaderScheduler with write_stage for leader to validator transitions
* Integrated LeaderScheduler with BroadcastStage
* Removed gossip leader rotation from crdt
* Add multi validator, leader test
* Comments and cleanup
* Remove unneeded checks from broadcast stage
* Fix case where a validator/leader need to immediately transition on startup after reading ledger and seeing they are not in the correct role
* Set new leader in validator -> validator transitions
* Clean up for PR comments, refactor LeaderScheduler from process_entry/process_ledger_tail
* Cleaned out LeaderScheduler options, implemented LeaderScheduler strategy that only picks the bootstrap leader to support existing tests, drone/airdrops
* Ignore test_full_leader_validator_network test due to bug where the next leader in line fails to get the last entry before rotation (b/c it hasn't started up yet). Added a test test_dropped_handoff_recovery go track this bug
carllin
Carl