This relocates tests that were improperly placed within the config pkg for both
the pkg/config and cmd/config packages. These were causing testutil to be imported
outside of tests causing a cyclic import issue when trying to import the config
pkg within the document pkg.
This patchset moves the tests as well as refactoring several of them where they
were leveraging private attributes which cannot be accessed as an external test
pkg.
Closes: #109
Relates-To: #107
Change-Id: Ib1bf2aff020599ba0b3f5a7fd7fadf737b8c86b8