Add CONTRIBUTING.md file to repo

[SpaceFace02]

Currently, we don't have any guidelines for contributing to our repository. Few things that are worth clarifying:

1. Commit message guidelines.
2. Branch name guidelines.
3. Commit segregation based on features added. One clear commit per feature/bug etc.
4. Guidelines to avoid large PRs
5. AI assisted information somewhere in commit message, if we have used AI to help us with a bug fix. For example Assisted by Claude or Co-authored by ....
6. Chain of sign-offs if needed.

reference:

1. https://github.com/kubernetes/community/blob/main/contributors/guide/contributing.md
2. https://docs.kernel.org/process/submitting-patches.html