**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'
```
bool supportsReplication() const override { return true; }
    bool supportsDeduplication() const override { return true; }
    Pipe read(
        const Names & column_names,
        const StorageMetadataPtr & ,
        SelectQueryInfo & query_info,
        ContextPtr context,
        QueryProcessingStage::Enum processed_stage,
        size_t max_block_size,
        unsigned num_streams) override;
    void read(
        QueryPlan & query_plan,
        const Names & column_names,
        const StorageMetadataPtr & ,
        SelectQueryInfo & query_info,
        ContextPtr context,
        QueryProcessingStage::Enum processed_stage,
        size_t max_block_size,
        unsigned num_streams) override;
    std::optional<UInt64> totalRows(const Settings & settings) const override;
    std::optional<UInt64> totalRowsByPartitionPredicate(const SelectQueryInfo & query_info, ContextPtr context) const override;
    std::optional<UInt64> totalBytes(const Settings & settings) const override;
    SinkToStoragePtr write(const ASTPtr & query, const StorageMetadataPtr & , ContextPtr context) override;
    bool optimize(
        const ASTPtr & query,
        const StorageMetadataPtr & metadata_snapshot,
        const ASTPtr & partition,
        bool final,
        bool deduplicate,
        const Names & deduplicate_by_columns,