[IMPROVEMENT] Support Scoop Proxy config

### Please confirm these before moving forward.

- [x] I have searched for my feature proposal and have not found a work-in-progress/duplicate/resolved/discarded issue.
- [x] This improvement refers to an existing feature. If you want to suggest a new feature, please use [this template](https://github.com/marticliment/WingetUI/issues/new?assignees=marticliment&labels=new-feature&projects=&template=feature-request.yml&title=%5BFEATURE+REQUEST%5D+%28Enter+your+description+here%29).
- [x] This improvement is not a bug. If you want to report a bug, please use [this template](https://github.com/marticliment/WingetUI/issues/new?assignees=marticliment&labels=bug&projects=&template=bug-issue.yml&title=%5BBUG%5D+%28Enter+your+description+here%29).

### Describe the improvement

According to the Scoop wiki, proxy configuration is officially supported:
https://github.com/ScoopInstaller/Scoop/wiki/Using-Scoop-behind-a-proxy

When the proxy toggle is turned on or off, UniGet can execute the corresponding PowerShell command:
```scoop config proxy '://:@:'```
and
```scoop config rm proxy```

### Describe how this improvement could help users

This feature could support the Scoop proxy config.