Allow ad-hoc revealing of private commands, flags, and environment variables

[DannyBen]

Adds a settings option (private_reveal_key), that if set, will allow users to reveal private commands, flags and environment variables by setting an environment variable with this name:

# settings.yml
private_reveal_key: PRIVATE_ACCESS

Discovered in #548

Todo

• Initial pilot
• Confirmed implementation
• Example
• Tests
• Update settings JSON schema
• Update mandoc rendering (separate PR)
• Update markdown rendering (separate PR)
• Update completions rendering (separate PR)
• Specs pass
• Rubocop pass
• Update doc site

Sample bashly.yml

name: cli
help: Sample application
version: 0.1.0

environment_variables:
- name: secret
  help: Set secret key
  private: true

flags:
- long: --debug
  help: Enable debug mode
  private: true

commands:
- name: admin
  help: Admin operations
  expose: true

  commands:
  - name: list
    help: List connected devices    
  - name: reboot
    help: Reboot
    private: true

[DannyBen]

@EmilyGraceSeville7cf - one more if you can: Minor change in settings schema
This one can either be nil or a string.