Write Dockerfile

[kissgyorgy]

A simple Dockerfile which has all required external dependencies installed.

[kukovecz]

Also, I think we need to refactor the gitub actions to build a container based on the Dockerfile and run the checks / tests inside that container.

The problem is, both the tests and checks github actions are doing a Install 3rd party from apt step. It would be easier to build a container and run everything from it.

The messy thing is, the checks sometimes does not need every package....
For example as I was checking this merge request: https://github.com/IoT-Inspector/unblob/pull/89/files
I just saw that it introduced a new dependency (lzop package) and this branch adds it to the tests github action, but it does not add it to the checks, and the checks can be executed.