✨ Configuration to adjust terminal letter spacing

### Describe the solution you'd like

This configuration variable will adjust the amount of spacing in between each character. This will be a multiple of the character itself.

### Examples

| Value | Description |
| - | - |
| 1 | no spacing in between characters |
| 1.5 | a half of a characters width between characters |
| 2 | a full characters width in between characters |

Note: We are not limited to the three values above, they are just examples to illustrate how this will work.

### Related issues

- #1101

未指定文件、测试或入口点。首先定位 Swift macOS 应用中的终端配置和字符渲染路径，并查看相关 issue #1101。完成的标准是：可配置的数值能够根据此 issue 中的示例改变字符间距。

由索引模型根据 Issue 内容生成。