add example to estimate area under line using montecarlo (#1782)

* add example to estimate area under line using montecarlo

* separate estimate func and print statements

* use mean from stats package

* avoid creating extra variable

* min_value: float=0.0, max_value: float=1.0

* Update montecarlo.py

* Update montecarlo.py

* Rename montecarlo.py to monte_carlo.py

* Update monte_carlo.py

Co-authored-by: Christian Clauss <[email protected]>