Move common parts of the tests into a common Bash script

[hhorak]

Many tests share similar or same parts, like:

• cleaning the containers after running the test
• running the container while storing the ID into a cidfile
• checking the man help.1 file
• ...

So we should eventually have at least set of functions shared in more containers to make the tests maintenance easier.

[praiskup]

Notable PR: #27.

[phracek]

This issue is obsolete everything was moved to common parts except databases.

And we do not have capacity for implementing this.