[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/RabbitMQConnectionProvider.cs

@@ -0,0 +1,35 @@
+using RabbitMQ.Client;
+
+namespace FictionArchive.Service.Shared.Services.EventBus.Implementations;
+
+public class RabbitMQConnectionProvider
+{
+    private readonly IConnectionFactory _connectionFactory;
+
+    private IConnection Connection { get; set; }
+    private IChannel DefaultChannel { get; set; }
+
+    public RabbitMQConnectionProvider(IConnectionFactory connectionFactory)
+    {
+        _connectionFactory = connectionFactory;
+    }
+
+    public async Task<IConnection> GetConnectionAsync()
+    {
+        if (Connection == null)
+        {
+            Connection = await _connectionFactory.CreateConnectionAsync();
+        }
+
+        return Connection;
+    }
+    
+    public async Task<IChannel> GetDefaultChannelAsync()
+    {
+        if (DefaultChannel == null)
+        {
+            DefaultChannel = await (await GetConnectionAsync()).CreateChannelAsync();
+        }
+        return DefaultChannel;
+    }
+}