Use const where appropriate

The value of a const field is computed at compile time and stored in the metadata, which improves run-time performance when it is compared to a static readonly field.

.editorconfig

@@ -179,8 +179,6 @@ dotnet_diagnostic.CA1720.severity = suggestion
 dotnet_diagnostic.CA1721.severity = suggestion
 dotnet_diagnostic.CA1724.severity = suggestion
 dotnet_diagnostic.CA1725.severity = suggestion
-dotnet_diagnostic.CA1801.severity = suggestion
-dotnet_diagnostic.CA1802.severity = suggestion
 dotnet_diagnostic.CA1805.severity = suggestion
 dotnet_diagnostic.CA1806.severity = suggestion
 dotnet_diagnostic.CA1810.severity = suggestion

src/NzbDrone.Core/Authentication/UserService.cs

@@ -19,14 +19,14 @@ namespace NzbDrone.Core.Authentication
 
     public class UserService : IUserService
     {
+        private const int ITERATIONS = 10000;
+        private const int SALT_SIZE = 128 / 8;
+        private const int NUMBER_OF_BYTES = 256 / 8;
+
         private readonly IUserRepository _repo;
         private readonly IAppFolderInfo _appFolderInfo;
         private readonly IDiskProvider _diskProvider;
 
-        private static readonly int ITERATIONS = 10000;
-        private static readonly int SALT_SIZE = 128 / 8;
-        private static readonly int NUMBER_OF_BYTES = 256 / 8;
-
         public UserService(IUserRepository repo, IAppFolderInfo appFolderInfo, IDiskProvider diskProvider)
         {
             _repo = repo;