Make README.md easier to read

[Samibanley]

This is the PR for issue #7

For this change, I moved all api documentation out the README.md and into their own separate markdown files, then referenced those files in the README. I put each endpoint in it's own collapsible section to allow the reader quick access to the information they need and updated the code snippets to use ES6.

With this change, the README is significantly smaller and makes maintaining documentation for each of the API calls a lot easier because you no longer have to dig through one massive file to edit the one call. You can just go to a more specific file and update it there.

[ashish8947]

@Samibanley Thanks for contributing to the repo. We can surely improve as per your suggestions. But as per the HacktoberFest guideline, we will not be accepting minor text fixes as a PR. Please suggest and improve some quantifiable changes in the pull request to make your PR eligible for HacktoberFest.

[Samibanley]

@ashish8947 I would certainly consider the work I did a quantifiable change. That was far more work than a "minor text fix."

Not only did I split all of the API documentation out into their own files, but I put them all into collapsible sections which took hours of wrapping every API call in a <details></details> and making sure that the summaries were correct, and that the format of everything still made sense. I went through thousands of lines of code. Your README.md is over 6,000 lines. This is a significant change to your documentation. This is not a spam PR.

I urge you to go to my branch and see the difference for yourself. It is a drastic improvement to user experience.

[Samibanley]

Whatever. No one is going to want to dig through that README. It's awful.