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

API/Data/Seed.cs

@@ -103,6 +103,7 @@ namespace API.Data
                 new() {Key = ServerSettingKey.ConvertBookmarkToWebP, Value = "false"},
                 new() {Key = ServerSettingKey.EnableSwaggerUi, Value = "false"},
                 new() {Key = ServerSettingKey.TotalBackups, Value = "30"},
+                new() {Key = ServerSettingKey.EnableFolderWatching, Value = "true"},
             }.ToArray());
 
             foreach (var defaultSetting in DefaultSettings)