Deal with `kb-sdk test` leaving root owned files on disk

[MrCreosote]

Options:

• Update kb-sdk so that containers don't run as root. Not sure how hard this would be or what downstream impacts it would have.
• Add a configuration setting (in .kbsdk.cfg? Don't think there's a config file for the SDK) that tells the SDK to delete all test files using a container
• Add a kb-sdk command to delete all test files using a container
• Same as the above two but just set test files to o+rwx