Added new sections & clarity to existing sections in README.md

[he-larious]

Changes include:

• Updated project description so it is easier to understand the app's purpose
• Added an image of a sample playlist's song being swapped to the rerecorded version
• Added a prerequisite section
• Modified 'Running it yourself' header to 'Installation' and made minor changes for readability and clarity to new users
• Added how to debug ERR_OSSL_EVP_UNSUPPORTED errors if the user is using Node.js v17+
• Added steps on how to contribute to the project
• Added a credits section
• Added a license section