Expand the Template Concept

[NikhilPeri]

The Template class is currently used as a testing utility to quickly create dataframes with default values.

However this concept can be expanded to serve as the contracts for any operation. Instead of specifying the dataset to read or write to instead you specify a Template which you would like to consume/produce which will contain:

• column names
• type definitions

This way the operation can enforce type and other values before writing a dataset, as well we can expand the scope of a dataset beyond csv files