Fix docker spawning issues

[semanser]

Closes #11, Closes #2

2024/03/25 12:14:52 Image node:latest found: false
2024/03/25 12:14:52 Pulling image node:latest...
2024/03/25 12:14:53 Creating container exec-test...
2024/03/25 12:14:53 failed to spawn container: %!w(*fmt.wrapError=&{Error creating container: Error response from daemon: No such image: node:latest {0xc000240120}})

The problem is due to the fact that ImagePull is an async function and according to the docs:

// ImagePull requests the docker host to pull an image from a remote registry.
// It executes the privileged function if the operation is unauthorized
// and it tries one more time.
// It's up to the caller to handle the io.ReadCloser and close it properly.

This means that we never actually wait for the image to be downloaded and simply continue with the flow even if the container is still downloading. https://github.com/semanser/codel/blob/7a7ba36a9511f9dc31549112cfab0f1fb44e459f/backend/executor/executor.go#L58-L62

[semanser]

• Added a new system messages to the terminal.
• Fixed docker loading issues.
• Simplified graphql schema
• Simplified the Input processing. Now it's processed in the same queue as all the other tasks.