YT-25934, YT-25935: Freeze Hydra followers on leader persistent crash

The proposed changes target the issue of a crash in a command for RSM, i.e. mutation. In particular, they implement:

* **freeze-hydra-peer** command to halt a follower mid-epoch, including persistent storage update;
* **truncate-changelog** command to drop uncommitted mutation records from the peer's replicated log instance;
* **schedule-restart** command to restart Hydra peer;
* **codicils watcher** background process in ytdaemon that detects a persistent crash of the leader process and issues *freeze-hydra-peer* to each follower.
commit_hash:bf9ac8c222f29ba31ed7e2a95ba9231be41b5e22

0 files changed, 0 insertions, 0 deletions