feat: improve config UI (#69)

* add first concept

* completed configuration ui update

* add button for testing email configuration

* improve mobile layout

* add migration

* run formatter

* delete unnecessary modal

* remove unused comment

backend/src/config/config.module.ts

@@ -1,10 +1,12 @@
 import { Global, Module } from "@nestjs/common";
+import { EmailModule } from "src/email/email.module";
 import { PrismaService } from "src/prisma/prisma.service";
 import { ConfigController } from "./config.controller";
 import { ConfigService } from "./config.service";
 
 @Global()
 @Module({
+  imports: [EmailModule],
   providers: [
     {
       provide: "CONFIG_VARIABLES",