Support optional description (or desc) field on Column and Check objects

[smackesey]

• This would be useful for tools that wrap Pandera and display rich schema info in a UI (Dagster has this planned)
• The description can already be specified in check functions specified in schema model classes.
• Built-in checks could generate their own descriptions based on args.

[smackesey]

@cosmicBboy Is this a feature you would accept a PR for?

[cosmicBboy]

yes! this feature has some overlap with #331

Basically the request is to add title and description to schemas and schema components for both the DataFrameSchema and SchemaModel syntax.

Would you be open to make a PR that addresses both issues? Basically these are all the components where title and description would make sense:

• DataFrameSchema (also applies to pandera.MultiIndex)
  • SchemaModel.Config would forward the properties to DataFrameSchema
• SeriesSchemaBase (this applies to SeriesSchema, Column, pandera.Index)
  • Field would forward the properties to Column/Index
• Check

I'm also open to a more incremental approach if you want to start with Column/Field and Check