feat(solution): Added solution for 0017

feat(solution): Added solutions for problem 2620, 2634, 2635

feat(solution): Added solutions for problem 9, 242, 273

feat(solution): Added more solutions and updated the solutions list

doc: Updated file names and links in solutions list

docs: Updated README with MIT licence icon

docs: Added LICENCE.md

docs: Updated solution URLs with URL encoded texts

docs: Added solutions list and updated README.md

feat(solution): Added C# solutions for Two Sum, Contains Duplicate, a…

docs: Added README.me