Added Caesar Cipher python implementation

[MPL0Y]

Caesar Cipher Python

Caesar Cipher is one of the oldest encryption techniques. It is a basic cryptography cipher method used to cipher a plaintext by merely shifting the characters based on the shift value (or key) provided.

Fixes # (issue)

Type of change

Please delete options that are not relevant.

• [x] New feature (non-breaking change which adds functionality)

Checklist:

• [x] My code follows the style guidelines of this project
• [x] I have performed a self-review of my own code
• [x] I have commented my code, particularly in hard-to-understand areas
• [x] I have made corresponding changes to the documentation
• [x] My changes generates no new warnings
• [x] I have added tests that prove my fix is effective or that my feature works
• [x] New and existing unit tests pass locally with my changes
• [x] Any dependent changes have been merged and published in downstream modules

[kaustubhgupta]

Looks like it's taken from here: https://www.tutorialspoint.com/cryptography_with_python/cryptography_with_python_caesar_cipher.htm

[MPL0Y]

I had this code saved on my machine. Didn't realise it could have been sourced. Sorry for the trouble. I'll be working on a command-line version of this.