Adding SkipList Algorithm

[github-ashwin]

 know more

Describe your change:

• [ x ] Add an algorithm?
• Fix a bug or typo in an existing algorithm?
• Documentation change?

Checklist:

• [ x ] I have read CONTRIBUTING.md.
• [ x ] This pull request is all my own work -- I have not plagiarized.
• [ x ] I know that pull requests will not be merged if they fail the automated tests.
• [ x ] This PR only changes one algorithm file. To ease review, please open separate PRs for separate algorithms.
• [ x ] All new JavaScript files are placed inside an existing directory.
• [ x ] All filenames should use the UpperCamelCase (PascalCase) style. There should be no spaces in filenames.
  Example:UserProfile.js is allowed but userprofile.js,Userprofile.js,user-Profile.js,userProfile.js are not
• All new algorithms have a URL in their comments that points to Wikipedia or another similar explanation.
• [ x ] If this pull request resolves one or more open issues then the commit message contains Fixes: #{$ISSUE_NO}.

[appgurueu]

This needs proper tests. The display() method is bad design; you should rather provide a function which returns an iterator to traverse the skip list.

[appgurueu]

As said, please write proper Vitest tests, don't just put example code into the file.