Describe your change:

This PR changes the existing base64_cipher.py with an easy to understand script that explains how the Base64 algorithm works under the hood. The solution is not necessarily faster, but I believe it will help people understand how the algorithm works and why it is possible to use Base64 in Steganography to conceal the existence of a piece of data.
Further more, I believe the base64_cipher.py name can be misleading as Base64 is considered an encoding, and not a cipher.

• Add an algorithm?
• Improve an existing solution.
• Fix a bug or typo in an existing algorithm?
• Documentation change?

Checklist:

• I have read CONTRIBUTING.md.
• This pull request is all my own work -- I have not plagiarized.
• I know that pull requests will not be merged if they fail the automated tests.
• This PR only changes one algorithm file. To ease review, please open separate PRs for separate algorithms.
• All new Python files are placed inside an existing directory.
• All filenames are in all lowercase characters with no spaces or dashes.
• All functions and variable names follow Python naming conventions.
• All function parameters and return values are annotated with Python type hints.
• All functions have doctests that pass the automated testing.
• All new algorithms have a URL in its comments that points to Wikipedia or other similar explanation.
• If this pull request resolves one or more open issues then the commit message contains Fixes: #{$ISSUE_NO}.