chore: No longer cache all background images (closes #365)

CHANGELOG.md

···
 - Fixed issue with missing extensions when downloading playlists.
 - Removed Fission/Webnative user layer (discontinued).
 - Minor improvements/fixes to the artwork downloading process.
+- No longer cache all background images when first loading the app.
 - A lot of javascript code refactoring.
 
 

system/Build/Build.gren

···
                                             { absolute = False
                                             }
                             )
+                    |> Array.filter (String.contains "images/Background/" >> (==) False)
                     |> Json.Encode.array Json.Encode.string
                     |> Json.Encode.encode 0
                     |> stringToBytes