[BUG] Various parts of UniGetUI need different representations for proxy information

### Please confirm these before moving forward

- [x] I have searched for my issue and have not found a work-in-progress/duplicate/resolved issue.
- [x] I have tested that this issue has not been fixed in the latest [(beta or stable) release](https://github.com/marticliment/WingetUI/releases/).
- [x] I have checked the [FAQ](https://github.com/marticliment/WingetUI#frequently-asked-questions) section for solutions.
- [x] This issue is about a bug (if it is not, please use the [correct template](https://github.com/marticliment/WingetUI/issues/new/choose)).

### UniGetUI Version

3.3.6

### Windows version, edition, and architecture

Microsoft Windows [Version 10.0.17763.316]

### Describe your issue

If within UniGetUI "Configuration -> Internet connection -> Proxy -> Proxy-URL" is configured to hold "http://127.0.0.1:3128" it will break some packet managers:

- UniGetUI: works as expected.
- WinGet: uses setting, does not work any more.
- Scoop: ignores setting.
- Chocolatey: uses setting, works
- NPM: ignores setting.
- PIP: uses setting, works.
- Cargo: uses setting, works.
- vcpkg: ignores setting.
- .NET: uses setting, works.
- PowerShell 5.x: uses setting, works.
- PowerShell 7.x: uses setting, works.

If proxy-environment-variables are set, but not UniGetUI-Proxy-Config:

`{ftp,http,https}_proxy=http://127.0.0.1:3128`

- UniGetUI: does not work, no connection to any server.
- WinGet: works.
- Scoop: seems to work.
- Chocolatey: works.
- NPM: works.
- PIP: works.
- Cargo: seems to work.
- vcpkg: works.
- .NET: works.
- PowerShell 5.x: works.
- PowerShell 7.x: works.

If no proxy-environmet-variables are given and no proxy-configuration is made within UniGetUI, but a proxy is distributed within the network:

- UniGetUI: does not work, no connection to any server.
- WinGet: works.
- Scoop: does not work.
- Chocolatey: works.
- NPM: does not work.
- PIP: does not work.
- Cargo: does not work.
- vcpkg: does not work.
- .NET: works.
- PowerShell 5.x: works.
- PowerShell 7.x: works.

Commandline options overwrite proxy-environment-variables.
proxy-environmet-variables overwrite proxy deploiment via network

For some pip-versions proxy-environment-variables must be lowercase, while other pip versions only accept uppercase variables. Later versions seem, at least on windows, accept upper and lowercase variables.

### Steps to reproduce the issue

1. Install UniGetUI, then WinGet, Scoop, NPM, PIP, Cargo, vcpkg, .Net-Tool, PowerShell 7.x
2. leave UniGetUI proxy settings untouched, do not define proxy-environment variables.
3. Test internet connectivity
4. Define proxy-environment-variables
5. Test internet connectivity
6. Undefine proxy-environment-variables, set proxy configuration within UniGetUI
7. Test internet connectivity
8. Define proxy-environment-variables, set proxy configuration within UniGetUI
9. Test internet connectivity

### UniGetUI Log

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### Package Managers Logs

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### Relevant information

### Screenshots and videos

_No response_