**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'
```
for (const auto it = disk->iterateDirectory(fs::path(relative_data_path) / "detached/"); it->isValid(); it->next())
        {
            MergeTreePartInfo part_info;
            if (!MergeTreePartInfo::tryParsePartName(it->name(), &part_info, format_version) ||
                part_info.partition_id != actual_part_info.partition_id)
                continue;
            const String part_old_name = part_info.getPartName();
            const String part_path = fs::path("detached") / part_old_name;
            const VolumePtr volume = std::make_shared<SingleDiskVolume>("volume_" + part_old_name, disk);
            
            MergeTreeData::MutableDataPartPtr part = createPart(part_new_name, actual_part_info, volume, part_path);
            try
            {
                part->loadColumnsChecksumsIndexes(true, true);
            }
            catch (const Exception&)
            {
                
                
                continue;
            }
            if (entry.part_checksum == part->checksums.getTotalChecksumHex())
            {
                part->modification_time = disk->getLastModified(part->getFullRelativePath()).epochTime();
                return part;
            }
        }
    return {};
}
bool StorageReplicatedMergeTree::executeLogEntry(LogEntry & entry)