chore: repo cleanup and code quality improvements

- Remove global.json (SDK pinning unnecessary)

- Remove nuget.config, move MyGet source to .csproj RestoreAdditionalProjectSources

- Gitignore ndepend/ entirely, move badges to docs/img/

- Update README.md and docs/ndepend.md badge paths

- Add NDepend project property to QuanTAlib.slnx

- Expand .editorconfig ReSharper/diagnostic suppressions

- Use ArgumentOutOfRangeException instead of ArgumentException

- Use discard _ for unused event sender parameters

- Remove quantalib.code-workspace and sonar-suppressions.json

- Add filter signature SVGs

lib/filters/baxterking/BaxterKing.cs

@@ -247,9 +247,6 @@ public sealed class BaxterKing : AbstractBase
         }
     }
 
-    [MethodImpl(MethodImplOptions.AggressiveInlining)]
-    private static double SoftBandPass(double value) => value;
-
     public static TSeries Batch(TSeries source, int pLow = 6, int pHigh = 32, int k = 12)
     {
         double[] input = source.Values.ToArray();