Update file paths for images and add CODEOWNERS file

[codebytes]

This pull request primarily focuses on updates to the README.md and CODEOWNERS files. The changes in the README.md file mostly involve updating image paths and adding a new resource link, while the CODEOWNERS file now includes default owners for the repository.

Here are the key changes:

Updates to README.md:

• The image paths for the AI Chat App Hack banner and the roadmap have been updated to relative paths, making them more robust and less dependent on the exact URL structure of the repository. [1] [2]
• A new resource, "AI-in-a-Box", has been added to the list of additional resources. This provides an additional source of information and examples for users.

Updates to CODEOWNERS:

• Default owners for the repository have been added. This means that @multispark, @jmc9000, and @cmaneu will be automatically requested for review on any changes to the repository, ensuring that the right people are always aware of and able to approve changes.

Other changes:

• The Banner 01 file was removed.

[multispark]

@pamelafox, Chris Ayers synced with me over teams! CODEOWNERS file should just have Pamela and Josh now.