Guide for setting up development environment

[dexhorthy]

I can't find any documentation on a development environment for community contributors to KOTS. CONTRIBUTING.md is empty.

I know @MikaelSmith has made a few contributions, perhaps you'd be willing to share your development / iteration loop? Or other @replicatedhq/core team members?

[MikaelSmith]

I've primarily done two things

• build and test the kots CLI: make kots, sometimes copy to /usr/local/bin/kubectl-kots.
• build and test the kotsadm service: followed https://github.com/replicatedhq/kots/blob/master/hack/CONTRIBUTING.md