[FEAT] Added greetings automations

[urs-santoshh]

Summary

This pull request adds greetings message automation for pull request and issues raised.

Pull request type

Please tick the type of change your PR introduces:

• [ ] Bugfix
• [x] Feature
• [ ] Code style update (formatting, renaming)
• [ ] Refactoring (no functional changes, no API changes)
• [ ] Build related changes
• [ ] Documentation content changes
• [ ] Other (please describe):

Checklist

Please review and complete the following checklist before submitting your pull request:

• [x] I have tested the changes locally and they work as intended.
• [ ] I have provided a detailed description of the changes made.
• [x] I have reviewed the formatting and ensured it follows the project's style guidelines.
• [ ] I have assigned the appropriate labels to the pull request.
• [ ] I have added necessary documentation or updated existing documentation for the changes made.
• [ ] I have addressed code review feedback and resolved any conflicts with the main branch.