Folder Watching (#1467)

* Hooked in a server setting to enable/disable folder watching

* Validated the file rename change event

* Validated delete file works

* Tweaked some logic to determine if a change occurs on a folder or a file.

* Added a note for an upcoming branch

* Some minor changes in the loop that just shift where code runs.

* Implemented ScanFolder api

* Ensure we restart watchers when we modify a library folder.

* Fixed a unit test

UI/Web/src/app/admin/_models/server-settings.ts

@@ -12,4 +12,5 @@ export interface ServerSettings {
     convertBookmarkToWebP: boolean;
     enableSwaggerUi: boolean;
     totalBackups: number;
+    enableFolderWatching: boolean;
 }