[FA-4] Adds an event bus infrastructure, a RabbitMQ implementation and rewires existing mutations on NovelService to utilize it.

FictionArchive.Service.Shared/Services/EventBus/Implementations/RabbitMQOptions.cs

@@ -0,0 +1,7 @@
+namespace FictionArchive.Service.Shared.Services.EventBus.Implementations;
+
+public class RabbitMQOptions
+{
+    public string ConnectionString { get; set; }
+    public string ClientIdentifier { get; set; }
+}