Removed confusing extra contributors folders

[rambasnet]

Extra contributors folders are deleted to not confuse users as to where to put the add-.txt file. Git-it app is updated to make it clear that users should add the file into CONTRIBUTORS folder inside the patchwork repo.

[reporobot]

Hello! The name of the branch with this Pull Request is not of the add-USERNAME pattern so I'm skipping reviewing it for the Git-it challenges. If you are completing the Git-it challenges, you'll need to close this Pull Request, rename your branch, push it to your fork of Patchwork on GitHub and then start a new Pull Request. Here's how to rename a branch and push it to GitHub from terminal:

$ git branch -m add-USERNAME
$ git push origin add-USERNAME