**Use case**

Currently, `system.replicas` table has `total_replicas` and `active_replicas` columns which are useful to check/alert when some replicas are down. One problem, these columns are numbers. They tell when there is a problem, but you need to further check ZooKeeper or query all the nodes to detect what exact replicas (hosts) are down/inactive/have problems.

**Describe the solution you'd like**

Add a replicas column maybe as a map which would contain the replica name, and it's status. Or, add 2 array columns with `replica_names` and `active_replica_names`

**Alternative**

Something along the line

```sql
select path, value from system.zookeeper where path IN (
    select concat(path, '/', name) from system.zookeeper where path in (select concat(zookeeper_path, '/replicas') from system.replicas)
)
and name = 'is_active'
```
Strings replicas = zookeeper->getChildren(fs::path(zookeeper_path) / "replicas");
                Coordination::Requests ops;
                for (const auto & path_part : replicas)
                {
                    Coordination::Stat stat;
                    String path = fs::path(zookeeper_path) / "replicas" / path_part / "host";
                    zookeeper->get(path, &stat);
                    ops.emplace_back(zkutil::makeCheckRequest(path, stat.version));
                }
                
                replica = findReplicaHavingPart(entry.new_part_name, true);
                
                
                if (replica.empty())
                {
                    Coordination::Stat quorum_stat;
                    const String quorum_unparallel_path = fs::path(zookeeper_path) / "quorum" / "status";
                    const String quorum_parallel_path = fs::path(zookeeper_path) / "quorum" / "parallel" / entry.new_part_name;
                    String quorum_str, quorum_path;
                    ReplicatedMergeTreeQuorumEntry quorum_entry;
                    if (zookeeper->tryGet(quorum_unparallel_path, quorum_str, &quorum_stat))
                        quorum_path = quorum_unparallel_path;
                    else
                    {
                        quorum_str = zookeeper->get(quorum_parallel_path, &quorum_stat);
                        quorum_path = quorum_parallel_path;
                    }
                    quorum_entry.fromString(quorum_str);
                    if (quorum_entry.part_name == entry.new_part_name)
                    {