Add PAC File Support to External Proxy Tool

[kics223w1]

Description

The macOS version of Proxyman already supports configuration using a PAC file. This ticket is a request to extend PAC file support to the Windows version of the app. The requester is using the Windows build inside a VM for testing and is unable to specify a PAC file in the Windows build at present

Notes

• Refer to windows app PAC file support Proxyman#2500

Acceptance Criteria

• The Windows build of Proxyman allows the user to input or reference a PAC file (via URL or local file path) in its proxy configuration settings.
• The PAC file is properly parsed and applied so that the proxy logic defined in the file (e.g., host/domain conditions, fallback proxies) is honored by the Windows app.