Test that package modules are accessible as symbols

[spbnick]

We'd like to be able to access the package modules as symbols after importing the package's module (__init__.py).

I.e. given the kcidb package contains the db module, this should work:

import kcidb
print(kcidb.db)

Most of the code is already built that way. However, we don't have any tests verifying that.

Add a test to test_kcidb.py which starts with the kcidb package, lists modules under it (e.g. using pkgutil, like in kcidb.monitor.subscriptions), imports the package and verifies that each listed module is available as a symbol with type <class 'module'> inside it, then continues to all sub-packages recursively, until everything is verified.

[octonawish-akcodes]

can I have a try at it :)

[spbnick]

Sure! This could be fun 😁 Let's finish with the currently-open PRs first, though.