Gmail handler

[Emiliohs02]

Summary

This PR introduces a GmailHandler class for interacting with Gmail accounts as a database in the evadb module.

Changes Made

• Implemented the GmailHandler class in the evadb.third_party.databases.types module.
• Added methods for connecting, disconnecting, checking connection status, retrieving tables, getting columns, and selecting and retrieving emails from a specified mailbox.
• Implemented a helper method _decode_header to decode email headers.
• Used the html2text library to convert HTML email bodies to plain text.
• Included error handling for robustness.

[github-actions]

👋 Hello @Emiliohs02, thanks for submitting a EVA DB PR 🙏 To allow your work to be integrated as seamlessly as possible, we advise you to:

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