Include information on columns for generating expressive frictionless schemas [FEATURE]

[johentsch]

Scope: anything that can be expressed according to this frictionless jsonSchema

• [ ] Field information
  • [ ] name
  • [ ] type
  • [ ] title
  • [ ] description (copy from docs)
  • [ ] constraints (required [= notna], unique, pattern, enum, minLength, maxLength, minimum, maximum)
  • [ ] (example)
• [ ] primaryKey

Mapping between Python (and pandas) object types to property sets:

• Fraction: string + pattern constraint
• Tuple: array
• int: integer + required=True
• Int64: integer + required=False (default)
• Categorical (pandas): string + enum constraint

[johentsch]

addressed via #77