Add ModelContextProtocol.AspNetCore (#160)

* Add ModelContextProtocol.AspNetCore

- Remove IServerTransport and HttpListenerSseServerTransport
- Replace HttpListenerSseServerTransport usage in tests with ASP.NET Core.

Co-authored-by: Eirik Tsarpalis <eirik.tsarpalis@gmail.com>
Co-authored-by: Jeff Handley <jeffhandley@users.noreply.github.com>

tests/ModelContextProtocol.TestSseServer/Properties/launchSettings.json

@@ -0,0 +1,12 @@
+{
+  "profiles": {
+    "ModelContextProtocol.TestSseServer": {
+      "commandName": "Project",
+      "launchBrowser": false,
+      "environmentVariables": {
+        "ASPNETCORE_ENVIRONMENT": "Development"
+      },
+      "applicationUrl": "http://localhost:3001"
+    }
+  }
+}