**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.
{
    Stopwatch watch;
    auto & entry_replace = *entry.replace_range_entry;
    LOG_DEBUG(log, "Executing log entry {} to replace parts range {} with {} parts from {}.{}",
              entry.znode_name, entry_replace.drop_range_part_name, entry_replace.new_part_names.size(),
              entry_replace.from_database, entry_replace.from_table);
    auto metadata_snapshot = getInMemoryMetadataPtr();
    auto storage_settings_ptr = getSettings();
    MergeTreePartInfo drop_range = MergeTreePartInfo::fromPartName(entry_replace.drop_range_part_name, format_version);
    
    bool replace = !LogEntry::ReplaceRangeEntry::isMovePartitionOrAttachFrom(drop_range);
    if (replace)
    {
        getContext()->getMergeList().cancelInPartition(getStorageID(), drop_range.partition_id, drop_range.max_block);
        queue.removePartProducingOpsInRange(getZooKeeper(), drop_range, entry);
        part_check_thread.cancelRemovedPartsCheck(drop_range);
    }
    else
    {
        drop_range = {};
    }
    struct PartDescription
    {
        PartDescription(