chore: initial repository scaffold

- Add Hrynco.RabbitMq class library with RabbitMQ client abstractions
- Add Hrynco.RabbitMq.Tests xunit project
- ImplicitUsings disabled on all projects

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

Hrynco.RabbitMq/IRabbitMqPublisher.cs

@@ -0,0 +1,9 @@
+namespace Hrynco.RabbitMq;
+
+using System.Threading;
+using System.Threading.Tasks;
+
+public interface IRabbitMqPublisher
+{
+    Task PublishAsync<TData>(string queue, IRabbitMqMessage<TData> message, CancellationToken cancellationToken = default);
+}