Added giphy.py to fetch gifs on a given topic (#5378)

* Added giphy.py to fetch gifs on a given topic

* Modified code
[*]Added doctest
[*]Formatted with black

* Minor change

* Minor refactoring to avoid name clash

* Made necessary changes as per review

* Update web_programming/giphy.py

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

* Apply suggestions from code review

* Final cleanup

* Placate psf/black

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