Added codechef scraper

[utkarsh1236]

Added a CodeChef Scraper using Selenium. Application automatically determines which scraper to use (CF or CC) based on the URL provided.

Following is a screenshot showing the input file after scraping a problem from CodeChef:

[akstron]

Try to brief about various parts of the code which you changed in comment, whenever you raise a pull request.

[utkarsh1236]

Thanks for the feedback @akstron !

Following are the changes that I made:

• Created a class called CCScraper modeled after CFScraper, with similar methods.
• Made changes to the Scraper.py file by adding import statements to use Selenium and the required web driver.
• Made changes to the __getResponse() method in Scraper class by adding a new parameter that tells whether the URL points to a dynamic website and then decides to either use requests or selenium accordingly.
• Made changes to the problem.py file to automatically detect whether the URL is of a CodeChef or a Codeforces problem.
• Also, added the Selenium version required for this application in the requirements.txt file.