Hashing (#634)

* Added the ability to see when a scan started at.

* filename based hashing now uses last write time as well to ensure if the underlying file changes it sends a new copy

* Fixed a bug where we would reset dark mode on the book reader to dark mode if our site was on dark mode, despite user setting light mode.

* Added a single feed entry when some sort of collection, reading list, etc doesn't have anything in it.

* Allow + in the normalization to prevent some series that use + to denote the sequel from not getting merged together.

API/Services/MetadataService.cs

@@ -139,6 +139,8 @@ namespace API.Services
         {
             var madeUpdate = false;
             if (series == null) return false;
+
+            // NOTE: This will fail if we replace the cover of the first volume on a first scan. Because the series will already have a cover image
             if (ShouldUpdateCoverImage(series.CoverImage, null, forceUpdate, series.CoverImageLocked))
             {
                 series.Volumes ??= new List<Volume>();