89 task implemet role based email system

[Aravinda-HWK]

📌 Description

This PR is to implement the role based email system.

• Closes [TASK] Implemet Role-Based Email System #89

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🔍 Changes Made

1. Add new tables to save role mail addresses and map them into real user mails.
2. Update delivery service to save the mails.
3. Update commands that relavant to retrieve the mails.

✅ Checklist (Email System)

• Core IMAP commands tested (LOGIN, CAPABILITY, LIST, SELECT, FETCH, LOGOUT).
• Authentication is tested.
• Docker build & run validated.
• Configuration loading verified for default and custom paths.
• Persistent storage with Docker volume verified.
• Error handling and logging verified
• Documentation updated (README, config samples).

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🧪 Testing Instructions

To test the server, use the instructions in the README in the test directory.

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📷 Screenshots / Logs (if applicable)

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⚠️ Notes for Reviewers

Still Silver side configuration was not done. Role mails and emails related to roles should be added by manually when testing.