Repo Preparation for MBO

[ThatGuyLLC]

This repo has been marked as core tech and is part of initiative of repo preparation, part of this includes adding needed missing documentation.
This repo in particular needs:

Explain how to make a contribution (Contributing MD)
Include the Standard Code of Conduct
Use the Apache 2.0 License or agreed alternative
Identify the Core Maintainers

[kderme]

This repo is no longer active and has been merged to https://github.com/input-output-hk/cardano-db-sync

[ThatGuyLLC]

got it, will inform kevin/marcin as well