Add review request email template for event attendees rsvp

[rituraj-OO7]

Description

closes #55

Adds the review request email template, enabling automated emails to be sent to event attendees with a direct link to submit feedback after the event ends, helping improve post-event engagement and insights

What type of PR is this? (Check all applicable)

• 🍕 Feature
• 🐛 Bug Fix
• 📄 Documentation Update
• 👨‍💻 Code Refactor
• 🔥 Performance Improvements
• ✅ Test
• 🛠️ CI/CD

Screenshots (if applicable)

Checklist

• I have performed a self-review of my code
• I have commented my code, particularly in hard-to-understand areas
• I have added tests that prove my fix is effective or that my feature works
• New and existing unit tests pass locally with my changes

[sonarqubecloud]

Quality Gate failed

Failed conditions
C Reliability Rating on New Code (required ≥ A)
B Maintainability Rating on New Code (required ≥ A)

See analysis details on SonarQube Cloud

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