Add a method that maps column names to actual data

[valengo]

For instance:

   def create_column_map(columns) -> defaultdict:
       """
       Create a dict based on columns
       :param list columns: list of columns
       :return: a dictionary mapping 'columns' values and indexes
       """
       columns_map = defaultdict(int)
       for i, column in enumerate(columns):
           columns_map[column] = i
       return columns_map