Add helper to ``cijoe`` instance

[safl]

In a cijoe script, it is common to rely on various command-line tools because one cannot depend on a wide range of Python versions and packages being available on the target system. To improve user experience, it would be helpful to test ahead of time whether the script would fail due to missing tools. This approach provides better error messages and allows the script to exit early if prerequisites are not met.

To facilitate this, a helper function such as::

cijoe.check_tools(tools: List[str])

should be added. This utility would support a commonly used idiom in cijoe scripting.