support Multi-disk(Multi-path)

### Search before asking

- [X] I had searched in the [issues](https://github.com/apache/incubator-kvrocks/issues) and found no similar issues.

### Motivation

When the host has multiple disks, multiple disks can be used for data storage to increase the performance of KVROCKS.
Hot data can be stored on local SSDS and cold data can be stored on cloud disks

### Solution

```
option.db_paths = {
{"/disk1", 1000 * 1000 * 1000},
{"/disk2", 1000 * 1000 * 1000},
{"/disk3", 1000 * 1000 * 1000},
{"/disk4", 1000 * 1000 * 1000}};
```

https://github.com/facebook/rocksdb/blob/main/include/rocksdb/options.h#L672

### Are you willing to submit a PR?

- [X] I'm willing to submit a PR!

Start with the linked RocksDB include/rocksdb/options.h entry for option.db_paths and compare that option with Kvrocks' storage configuration. The issue names no Kvrocks files or tests, so first identify the storage integration points and how disk paths should support the stated hot- and cold-data use case. Done should include a defined multi-disk configuration and validation of its behavior.

Written by the indexing model from the issue text.