
**Bug description**
Unlike `cluster()`, `clusterAllReplicas()` does not implement `_shard_num`. 

I would expect
```
SELECT _shard_num
FROM clusterAllReplicas(prod, system.one)
ORDER BY _shard_num ASC
FORMAT PrettyCompactMonoBlock

┌─_shard_num─┐
│          0 │
│          0 │
│          0 │
│          0 │
│          0 │
│          0 │
│          0 │
│          0 │
│          0 │
│          0 │
│          0 │
│          0 │
│          0 │
│          0 │
│          0 │
│          0 │
│          0 │
│          0 │
│          0 │
│          0 │
│          0 │
│          0 │
│          0 │
│          0 │
│          0 │
│          0 │
│          0 │
│          0 │
│          0 │
│          0 │
└────────────┘
```
to have an output more useful like
```
SELECT _shard_num
FROM cluster(prod, system.one)
ORDER BY _shard_num ASC
FORMAT PrettyCompactMonoBlock

┌─_shard_num─┐
│          1 │
│          2 │
│          3 │
│          4 │
│          5 │
│          6 │
│          7 │
│          8 │
│          9 │
│         10 │
│         11 │
│         12 │
│         13 │
│         14 │
│         15 │
└────────────┘
```

**Releases where this has been tested**

* v20.3.12.112-stable

**References**

[cluster, clusterAllReplicas documentation](https://clickhouse.tech/docs/en/sql-reference/table-functions/cluster/)

[_shard_num documentation](https://clickhouse.tech/docs/en/engines/table-engines/special/distributed/#virtual-columns)

#include <Interpreters/Cluster.h>
#include <common/SimpleCache.h>
#include <Common/DNSResolver.h>
#include <Common/escapeForFileName.h>
#include <Common/isLocalAddress.h>
#include <Common/StringUtils/StringUtils.h>
#include <Common/parseAddress.h>
#include <Common/Config/AbstractConfigurationComparison.h>
#include <Core/Settings.h>
#include <IO/WriteHelpers.h>
#include <IO/ReadHelpers.h>
#include <Poco/Util/AbstractConfiguration.h>
#include <Poco/Util/Application.h>
#include <ext/range.h>
#include <boost/range/algorithm_ext/erase.hpp>
namespace DB
{
namespace ErrorCodes
{
    extern const int UNKNOWN_ELEMENT_IN_CONFIG;
    extern const int EXCESSIVE_ELEMENT_IN_CONFIG;
    extern const int LOGICAL_ERROR;
    extern const int SHARD_HAS_NO_CONNECTIONS;
    extern const int SYNTAX_ERROR;
}
namespace
{
constexpr UInt32 default_weight = 1;
inline bool isLocalImpl(const Cluster::Address & address, const Poco::Net::SocketAddress & resolved_address, UInt16 clickhouse_port)