Feature/email support (#720)

* feat(frontend): ✨ add UI for testing email configuration

* feat(backend): ✨ add email service with common templates (WIP)

* test(backend): ✅ add basic tests for email configuration

* set defaults

* add email variables

Co-authored-by: Hayden <hay-kot@pm.me>

frontend/api/index.ts

@@ -15,6 +15,7 @@ import { WebhooksAPI } from "./class-interfaces/group-webhooks";
 import { AdminAboutAPI } from "./class-interfaces/admin-about";
 import { RegisterAPI } from "./class-interfaces/user-registration";
 import { MealPlanAPI } from "./class-interfaces/group-mealplan";
+import { EmailAPI } from "./class-interfaces/email";
 import { ApiRequestInstance } from "~/types/api";
 
 class AdminAPI {
@@ -50,6 +51,7 @@ class Api {
   public groupWebhooks: WebhooksAPI;
   public register: RegisterAPI;
   public mealplans: MealPlanAPI;
+  public email: EmailAPI;
 
   // Utils
   public upload: UploadFile;
@@ -83,6 +85,8 @@ class Api {
     this.upload = new UploadFile(requests);
     this.utils = new UtilsAPI(requests);
 
+    this.email = new EmailAPI(requests);
+
     Object.freeze(this);
     Api.instance = this;
   }