feat: Add preset shift templates, admin SMTP settings, test email dispatch, and email verification opt-out option

backend/apps/users/serializers.py

@@ -1,6 +1,6 @@
 from rest_framework import serializers
 from django.contrib.auth import get_user_model
-from .models import RegistrationDomainRule, RegistrationRestrictionSetting
+from .models import RegistrationDomainRule, RegistrationRestrictionSetting, SMTPSetting
 from apps.events.models import Skill
 
 User = get_user_model()
@@ -77,4 +77,9 @@ class RegistrationDomainRuleSerializer(serializers.ModelSerializer):
 class RegistrationRestrictionSettingSerializer(serializers.ModelSerializer):
     class Meta:
         model = RegistrationRestrictionSetting
-        fields = ['is_restriction_enabled', 'require_admin_approval']
+        fields = ['is_restriction_enabled', 'require_admin_approval', 'require_email_verification']
+
+class SMTPSettingSerializer(serializers.ModelSerializer):
+    class Meta:
+        model = SMTPSetting
+        fields = ['is_active', 'host', 'port', 'username', 'password', 'use_tls', 'use_ssl', 'from_email']