Gmoshkin/join using batch dml

Summary

• fix: initialize replicaset atomically with the first joined instance

• fix: use batch-dml when joining instances for robustness

• chore: stop sentinel from spamming logs with info messages

• fix: rustfmt woke up

• fix: better BatchDml display in pico.raft_log()

• fix: pico.raft_log() broke after updating tarantool-sys

• Close #...
• Changes should be cherry-picked to 24.2: no
• Docs follow-up: docs#229 (closed)