feat: support select for redis compatibility (#201)

Author: xiaopeng8570

en_US/key-value-data-model/redis-compatibility.md

@@ -5,6 +5,7 @@ The current implementation of the Datalayers Key-Value supports a subset of Redi
 | Command Category | Command | Support Level | Comments |
 | --- | --- | --- | --- |
 | **Connection Management** | PING | Fully Supported |     |
+|     | SELECT | Fully Supported | Supported index: [0, 65535]  |
 | **Generic** | KEYS | Fully Supported |     |
 |     | DEL | Fully Supported |     |
 | **Transaction** | MULTI | Fully Supported |     |

zh_CN/key-value-data-model/redis-compatibility.md

@@ -5,6 +5,7 @@
 | <div style="width:150px">命令类别</div>        | 命令      | <div style="width:100px">支持级别</div>     | 备注 |
 | ---           | ---       | ---         | --- |
 | **连接管理**    | PING     | 完全支持      |     |
+|                | SELECT   | 完全支持      | 支持 [0, 65535] 范围内的 index   |
 | **通用命令**    | KEYS     | 完全支持      |     |
 |                | DEL      | 完全支持      |     |
 | **事务**       | MULTI     | 完全支持      |     |