TCF (0.5.0): Добавить пример `кластер Tarantool Cartridge + кластер Tarantool 3 EE` с etcd/config_storage

**Product:** TCF
**Root document:** user guide
**Doc version:** latest (0.3.x+)
**SME:** @ DifferentialOrange @ oleg-jukovec @ themilchenko

# Details

https://github.com/tarantool/cluster-federation/tree/master/example/tarantool2_to_tarantool3_with_etcd

https://github.com/tarantool/cluster-federation/tree/master/example/tarantool2_to_tarantool3_with_tarantool_config_storage