chore: Vendor neutrality

[scottrigby]

To-do

• Apache license 948374f
• Remove replicated steps from CONTRIBUTING.md 948374f
• Moving the built-in Replicated tooling to a configurable list of supported integrations that people can turn on or off
  Then anyone will be able to contribute PRs for integrations with other vendors and projects
• Update contributing guidelines
• Add simple governance for the project and look for maintainers from other companies
• other things?

Open questions

• Will this be proposed as a CNCF sandbox project? Proposed as a Helm subproject?
  This is a very early project so let's see where it goes