Document environment variables for otomi-cli

[j-zimnowoda]

The usage of env flags may be confusing for developers. It might not be clear what these flags do. We should document them in our README.md. Flags that are in use now:

• CI
• TESTING
• IN_DOCKER
• VALUES_INPUT
• ??

Use cases we use them in now are:

• CI: when ran by any CI runner, such as Github actions, or Drone. Intended to indicate unattended install
• IN_DOCKER: used by otomi cli to inject into the container to let the entry point script know wether to execute a command in docker or not (not when IN_DOCKER ;)
• TESTING: Used by to run tests (see npm test). Sets CI to true and ENV_DIR to tests/fixtures.
• VALUES_INPUT: set by the chart installer to the values file, also used to populate a new ENV_DIR with VALUES_INPUT=/some/values.yaml otomi bootstrap

[Morriz]

I want to ask to start any ideas on the new scrum discussion board.