This is a convenient way for tests to assert that some nested dicts
(like a parsed json) has a particular key/value somewhere in it.
For example:
assert_dict_has(config, "toplevel.subitem.key", True)
This commit adds `osbuild.testutil.imports.import_module_from_path`
that can be used to import arbitrary python source files. This
allows importing files from the stages directory that have a
non python friendly filename like `org.osbuild.kickstart`.
