Use apt-get instead of apt

[mks-h]

Using apt CLI in scripts leads to this warning:

WARNING: apt does not have a stable CLI interface. Use with caution in scripts.

From apt's manpage:

apt provides a high-level commandline interface for the package management system. It is intended as an end user interface and enables some options better suited for interactive usage by default compared to more specialized APT tools like apt-get(8) and apt-cache(8).

So Vib should use stable apt-get CLI instead of apt

[lambdaclan]

Hello there. I would like to work on this task. I have created a preliminary pull request #51 for your review. I will be happy to do any adjustments if at all necessary, so please let me know. Thank you.