[3.x] TDB (iproto): recommendations for supervised failover

**Related issue(s):** 
**Product:** Tarantool DB
**Since:** 3.0
**Root document:** https://www.tarantool.io/en/tarantooldb/doc/latest/admin_guide/failover/
**SME:** @ a1div0 @ Satbek 

# Details

recommendations for tdb 1.x: https://www.tarantool.io/en/tarantooldb/doc/1.x/admin_guide/failover/stateful_etcd/#admin-guide-failover-stateful-etcd