Add MFA support

app/services/MFA.service.js

@@ -0,0 +1,27 @@
+const { Service } = require('flitter-di')
+const speakeasy = require('speakeasy')
+const qrcode = require('qrcode')
+
+class MFAService extends Service {
+    static get services() {
+        return [...super.services, 'configs']
+    }
+
+    secret(user) {
+        return speakeasy.generateSecret({
+            length: this.configs.get('auth.mfa.secret_length') ?? 20,
+            name: `${this.configs.get('app.name')} (${user.uid})`,
+        })
+    }
+
+    async qr_code(secret) {
+        return new Promise((resolve, reject) => {
+            qrcode.toDataURL(secret.otpauth_url, (err, image_data) => {
+                if ( err ) reject(err)
+                else resolve(image_data)
+            })
+        })
+    }
+}
+
+module.exports = exports = MFAService