**Describe the solution you'd like**

We already can run clickhouse-server without configured ZooKeeper (the tables will start in read-only mode)
and with configured ZooKeeper, if it starts to be inaccessible at runtime (the tables will be read-only until the session is re-established).

Let's also make it possible to start up when ZooKeeper is unavailable.

**Additional context**

If that will be very hard to implement, we can consider other options:
- lazy attaching of the tables after sever start-up;
- a maintenance mode when the tables are not attached at start-up and require manual ATTACH queries.
{
    auto zk_path = tryExtractZkPathFromCreateQuery(create_query, global_context);
    if (!zk_path)
        return {};
    String zk_name = zkutil::extractZooKeeperName(*zk_path);
    zk_path = zkutil::extractZooKeeperPath(*zk_path, false, nullptr);
    zkutil::ZooKeeperPtr zookeeper = (zk_name == getDefaultZooKeeperName()) ? global_context->getZooKeeper() : global_context->getAuxiliaryZooKeeper(zk_name);
    String id;
    if (!zookeeper->tryGet(fs::path(*zk_path) / "table_shared_id", id))
        return {};
    return id;
}
void StorageReplicatedMergeTree::lockSharedDataTemporary(const String & part_name, const String & part_id, const DiskPtr & disk) const