Add folder-based split tunneling support

[xacnio]

Issue

Some applications may have dynamic .exe paths, so app-based split tunneling alone is not enough.

For example: When Discord released an update, the app path changes "app-1.0.9228" -> "app-1.0.9229"
\Discord\app-1.0.9228\Discord.exe --> \Discord\app-1.0.9229\Discord.exe"

It forces us to re-add the application and re-connect vpn every time it updates.

Solution

Folder-based split tunneling.

• Scans executables recursively.
• Watches folder changes and add/remove execution paths dynamically.
• Disabling/Enabling/Adding/Deleting works dynamically.
• Uses WFP & Callout transaction method. (dynamic app rules, no reconnection)

Risks

• When selected a folder/root folder that has many sub-directories, .exes like C:/.
  » Up to the user, possible client-side performance issues.
  » No constraints applied.
• When user selected so many folders (100+)
  » FileSystemWatcher may encounter issues.
  » Folder count is limited to 50.

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