feat: Implement smtp connection

packages/backend/src/apps/smtp/auth/verify-credentials.ts

@@ -0,0 +1,22 @@
+import { IGlobalVariable } from '@automatisch/types';
+import nodemailer, { TransportOptions } from 'nodemailer';
+
+const verifyCredentials = async ($: IGlobalVariable) => {
+  const client = nodemailer.createTransport({
+    host: $.auth.data.host,
+    port: $.auth.data.port,
+    secure: $.auth.data.useTls,
+    auth: {
+      user: $.auth.data.username,
+      pass: $.auth.data.password,
+    },
+  } as TransportOptions);
+
+  await client.verify();
+
+  await $.auth.set({
+    screenName: $.auth.data.username,
+  });
+};
+
+export default verifyCredentials;