04-chaining-selectors: Updated index.html and README.md

[jasonguf]

Because

This pull request contains the updated index.html file with the src attributes for the images already pre-populated so that the user doesn't have to fill them out. A new folder called "images" is also added which contains the required images for this exercise. Lastly, the README.md file is updated and it no longer contains the note telling the user to download the images and to add them to the "images" folder.

This PR

• Updated the index.html file with the src attributes for the images
• Added the required images for the exercise into a new folder called "images"
• Updated the README.md file by removing the note about downloading the images and placing them into the "images" folder

Issue

Closes #448

Additional Information

Pull Request Requirements

• I have thoroughly read and understand The Odin Project Contributing Guide
• The title of this PR follows the location of change: brief description of change format, e.g. 01-flex-center: Update self check
• The Because section summarizes the reason for this PR
• The This PR section has a bullet point list describing the changes in this PR
• If this PR addresses an open issue, it is linked in the Issue section
• If applicable, I have ensured that the TOP solution files match the Desired Outcome image

[thatblindgeye]

In the future @jasonguf please wait to be assigned an issue before submitting a PR. Another user had asked to be assigned first and the issue would have gone to them, and it also helps prevent multiple users submitting a PR for the same issue without realizing.