Create newton_backward_interpolation.py

[quanta003]

Describe your change:

Added "Newton Backward Interpolation" code

• [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 Python files are placed inside an existing directory.
• [x] All filenames are in all lowercase characters with no spaces or dashes.
• [x] All functions and variable names follow Python naming conventions.
• [x] All function parameters and return values are annotated with Python type hints.
• [x] All functions have doctests that pass the automated testing.
• [x] All new algorithms have a URL in its comments that points to Wikipedia or other similar explanation.
• [x] If this pull request resolves one or more open issues then the commit message contains Fixes: #{$ISSUE_NO}.

[quanta003]

Please merge it if no issues found @spazm @CaedenPH @darkstar @bit-man

[tianyizheng02]

Thanks for your contribution, but unfortunately there are too many issues with this PR for us to merge and you never fixed them following @CaedenPH's code review. Apart from the issues that he pointed out, your algorithmic code is almost entirely contained within a main block rather than separate functions. In addition, there should be minimal side effects, so printing should be avoided when possible. Please read the contributing guidelines if you wish to contribute.