Create Base64 and Env File Tutorial

### Overview

Write a tutorial on base64 and usage of .env files based on experience using them when completing automation dashboard project for Hack for LA website team. This would be useful for a data scientist/ analyst who needs to upload their Python script to a GitHub repository without compromising the security of confidential API keys and other (privacy) information.

### Action Items
- [ ] Create an introduction that gives context as to the purpose/use of the tutorial and connects the 2 concepts based on commonality
- [x] Create full walkthroughs of process to use both
- [x] Search for useful resources to complement tutorial
- [x] Add screenshots and resize them to appropriate sizes
- [x] Proofread for misleading language
- [x] Message Sophia and Karina to get tutorial approved

### Resources/Instructions
All resources have been included in the body of the tutorial

Wiki Tutorial Created: [Introduction to Keeping Confidential Information Safe on GitHub: GitHub secrets and .env files](https://github.com/hackforla/data-science/wiki/Introduction-to-Keeping-Confidential-Information-Safe-on-GitHub:-GitHub-secrets-and-.env-files)