Debug router command

[Blacksmoke16]

• [feature] Add first built-in command to debug the available routes
• [feature] Add command to debug which, if any, a request path would resolve to
• [feature] Add #has_scheme? method to ART::Route
• [enhancement] Make testing commands with input more robust
  • Avoids an infinite loop if the command expects input and there are none left to consume
• [enhancement] Allow nil as cell values
• [enhancement] Add actual dependency on athena-console to framework component
  • Was missed in #218, but the version does not actually exist yet