Add predictable error output formatting and color support

[rwxrob]

The look and feel of bonzai commands should be consistent and clean, just like with the help documentation, but with stronger opinions about what they should look like so that bad error messages are discouraged in the Bonzai ecosystem. Error text can therefore be handled consistently.

• Assume error type or location before : (color strongly)
• Assume anything after : is key text of error (color legibly)
• Assert blank new line and add if not
• Assume everything else is boring, verbose explanation (muted color, but legible)

Use only standard terminal colors so that they change with terminal themes.