.NET: Rename workflows projects (#975)

* Renaming Microsoft.Agent.Workflows to Microsoft.Agents.AI.Workflows

* Removing local settings.

* Removing remining old files from merge.

dotnet/src/Microsoft.Agents.AI.Workflows/StreamsMessageAttribute.cs

@@ -0,0 +1,27 @@
+// Copyright (c) Microsoft. All rights reserved.
+
+using System;
+using Microsoft.Shared.Diagnostics;
+
+namespace Microsoft.Agents.AI.Workflows;
+
+/// <summary>
+/// This attribute indicates that a message handler streams messages during its execution.
+/// </summary>
+[AttributeUsage(AttributeTargets.Class | AttributeTargets.Method, AllowMultiple = true)]
+public sealed class StreamsMessageAttribute : Attribute
+{
+    /// <summary>
+    /// The type of the message that the handler yields.
+    /// </summary>
+    public Type Type { get; }
+
+    /// <summary>
+    /// Indicates that the message handler yields streaming messages during the course of execution.
+    /// </summary>
+    public StreamsMessageAttribute(Type type)
+    {
+        // This attribute is used to mark executors that yield messages.
+        this.Type = Throw.IfNull(type);
+    }
+}