Seperate contributing.md

[siddish-reddy]

Provide clear instructions on how one can contribute to either code, documentation or UX of the app

1. App philosophy and principles.
2. Coding Style Guide in Contribution.md (Variables, functions, modules naming, white spaces, line lengths, etc)
3. Pull request checklist.
4. Issue reporting approach and template.
5. Documentation style guides, design system resources and files.