Tech Debt + Series Sort bugfix (#1192)

* Code cleanup.

When copying files, if the target file already exists, append (1), (2), etc onto the file (this is enhancing existing implementation to allow multiple numbers)

* Added a ton of null checks to UpdateSeriesMetadata and made the code work on the rare case (not really possible) that SeriesMetadata doesn't exist.

* Updated Genre code to use strings to ensure a better, more fault tolerant update experience.

* More cleanup on the codebase

* Fixed a bug where Series SortName was getting emptied on file scan

* Fixed a bad copy

* Fixed unit tests

API/Data/DbFactory.cs

@@ -18,7 +18,7 @@ namespace API.Data
     {
         public static Series Series(string name)
         {
-            return new ()
+            return new Series
             {
                 Name = name,
                 OriginalName = name,