Update sanbox minicli sample

[devatreides]

This PR modifies the current minicli app in the sandbox. As a new user of the tool, I felt that convert the current code into a more organized one (using command controllers) is a little tricky. For me, the controller approach seems to be more friendly to new users and makes easy to read not only the code but the project itself.

For that, I made some changes in the minicli script to map the commands created in the app folder and wrote a simple command to work as an example about how to start.