Consolidate `dbtype-commands.txt` files for easier maintainability

As a next step to #471, move the commands that are common to all database types to a common file.

Benefits in performing this:

1. This ensures that changes have to be made at only one place
2. Latest updates to config files will be reflected across all SQL database types.

首先，在仓库中定位每个 dbtype-commands.txt 文件，并比较各 SQL 数据库类型之间的命令。确定哪些命令是共用的，并确定每个数据库配置如何引用这些命令。当共用命令在一个共享文件中维护，并且更新能够反映到所有 SQL 数据库配置中时，即视为完成。

由索引模型根据 Issue 内容生成。