Service refactor (#153)

* remove email out of register service

* Update auth service, move JWT handling out of controller

* add docker config for service auth test

* Update mock email system

* Format: ./src/Core/Service

* Refactor authentication payloads and services for registration and login processes

* Format: src/Core/API, src/Core/Service

src/Core/Service/Service.Emails/EmailService.cs

@@ -0,0 +1,41 @@
+using Domain.Entities;
+using Infrastructure.Email;
+using Infrastructure.Email.Templates.Rendering;
+
+namespace Service.Emails;
+
+public interface IEmailService
+{
+    public Task SendRegistrationEmailAsync(
+        UserAccount createdUser,
+        string confirmationToken
+    );
+}
+
+public class EmailService(
+    IEmailProvider emailProvider,
+    IEmailTemplateProvider emailTemplateProvider
+) : IEmailService
+{
+    public async Task SendRegistrationEmailAsync(
+        UserAccount createdUser,
+        string confirmationToken
+    )
+    {
+        var confirmationLink =
+            $"https://thebiergarten.app/confirm?token={confirmationToken}";
+
+        var emailHtml =
+            await emailTemplateProvider.RenderUserRegisteredEmailAsync(
+                createdUser.FirstName,
+                confirmationLink
+            );
+
+        await emailProvider.SendAsync(
+            createdUser.Email,
+            "Welcome to The Biergarten App!",
+            emailHtml,
+            isHtml: true
+        );
+    }
+}