Add CONTRIBUTING.md files in github repo
|Reported by:||bakaniko||Owned by:||bakaniko|
A common practice in FOSS is to provide in github repositories a CONTRIBUTING.md files where people can find easily guidelines for contributing.
We don't have such, and we (or at least me) struggle to provide information to newcomers.
Things to provide:
- legal stuff ("I'd like to contribute to... My contributions.."
- full git workflow from cloning to the pull request