Add Directory.Build.props. (#2120)

* Add Directory.Build.props.

* Adjust Analysis related properties and add conditional enablement for ContinuousIntegrationBuild.

* Adopt new changes in master

---------

Co-authored-by: christian <6939810+chkr1011@users.noreply.github.com>

Source/MQTTnet.Benchmarks/ChannelAdapterBenchmark.cs

@@ -15,7 +15,7 @@ using MQTTnet.Tests.Mockups;
 namespace MQTTnet.Benchmarks;
 
 [MemoryDiagnoser]
-public sealed class ChannelAdapterBenchmark : BaseBenchmark
+public sealed class ChannelAdapterBenchmark : BaseBenchmark, IDisposable
 {
     MqttChannelAdapter _channelAdapter;
     int _iterations;
@@ -86,4 +86,10 @@ public sealed class ChannelAdapterBenchmark : BaseBenchmark
 
         return buffer.ToArray();
     }
+
+    public void Dispose()
+    {
+        _channelAdapter?.Dispose();
+        _stream?.Dispose();
+    }
 }