refactor: move VFS location

- Moved the location of the VFS outside the plugins directory, so it
  won't be scanned on startup by Jellyfin when it tries to discover
  the plugins to load. Also, in case it wasn't obvious enough.
  THIS IS A BREAKIGN CHANGE. Okay? Okay.

Shokofin/Plugin.cs

@@ -24,13 +24,14 @@ public class Plugin : BasePlugin<PluginConfiguration>, IHasWebPages
     /// <summary>
     /// "Virtual" File System Root Directory.
     /// </summary>
-    public string VirtualRoot => Path.Combine(DataFolderPath, "VFS");
+    public readonly string VirtualRoot;
 
     public Plugin(IApplicationPaths applicationPaths, IXmlSerializer xmlSerializer, ILogger<Plugin> logger) : base(applicationPaths, xmlSerializer)
     {
         Instance = this;
         ConfigurationChanged += OnConfigChanged;
         IgnoredFolders = Configuration.IgnoredFolders.ToHashSet();
+        VirtualRoot = Path.Combine(applicationPaths.ProgramDataPath, "Shokofin", "VFS");
         Logger = logger;
         Logger.LogInformation("Virtual File System Location; {Path}", VirtualRoot);
     }