Add defaults and a selector to interactive mode

[aidnem]

• Replace selection inputs (picking mechanism type or lead motor) with a Pick library picker:

• note: Adds a custom wrapper around pick.pick to spoof the selection output so the terminal history includes the selector result:

• Uses prompt_toolkit to defaults for package (auto-fills subsystems. and lets user type the rest) and CAN bus (auto-fills canivore)
• Uses prompt_toolkit to auto-complete for motors and encoders (press tab to add Motor or Encoder:

[PChild]

Looks good. Everything worked for me when I tested it.