Add bats tests for docker image

[tzdybal]

Overview

Resolves #2 .

Checklist

• New and updated code has appropriate documentation
• New and updated code has new and/or updated testing
• Required CI checks are passing
• Visual proof for any user facing features like CLI or documentation updates
• Linked issues closed with keywords

[nashqueue]

**This summary was created by my experimental bot **This diff is a script written in the Bats testing framework. It sets up a Docker container, runs two tests, and tears down the container. The first test checks if the Celestia appd is producing blocks by making an HTTP request to a specific block height. The second test checks if the Celestia node is processing blocks by making an HTTP request to the head of the blockchain. Both tests have a loop that runs for 30 seconds, waiting for the expected response and setting the "ok" variable to true if successful. There are no alterations to the signatures of exported functions or global data structures mentioned in the diff.