improvement: twilio autopilot:fields:create

[pranavdesh]

Currently this command requires the user to provide 4 arguments that can be time consuming to retrieve. Proposal:

• Make assistant SID and the unique name as the only required commands. Task sid and field type sid can be optional.
• If the user does not provide task sid and field type sid, list all tasks by their unique name in the assistant and ask the user to select one
• then, list all field types in the assistant and all the built-in field types provided by Twilio and ask the user to select one for creating their field.
• also display a message saying 'Use twilio autopilot:fieldtypes:create if you need to create a new field type.' At this point the user can choose to exit the command to create a new field type
• Finally, once the user selects a task and field type, create the field.

[pranavdesh]

Functionality works. Please change the first bit of text to 'Choose a Task for the new Field:' and the second bit to 'Choose a Field Type for the new Field:'