Create 3o2.2.spot_identity_matrix.py

# By Ashwath from forums
# Given a list of lists representing a n * n matrix as input, 
# define a  procedure that returns True if the input is an identity matrix 
# and False otherwise.

# An IDENTITY matrix is a square matrix in which all the elements 
# on the principal/main diagonal are 1 and all the elements outside 
# the principal diagonal are 0. 
# (A square matrix is a matrix in which the number of rows 
# is equal to the number of columns)