Add problems and solutions from Project Euler

[Vishruth-S]

The project_euler_problems folder currently has only a very few problems. It would be nice if more interesting questions and their solutions be added from Project Euler

Refer Contribting.md and read all points carefully before sending a Pull request.

Keep this in mind: When adding solutions, ensure that you provide sufficient comments so as to explain the logic used. More emphasis is given on understanding the technique used rather than the code itself 😃

Happy Contributing 😄

[amanbedi1]

Look at my PR. #579

As this is my first PR so if there is anything i have to rectify please let me know