Revert addition of Steno logger

These changes depend on an unreleased version of Steno, which breaks
projects that depend on the vcap_common gem unless they also depend on
the same unpublished version of Steno

This reverts commit eeff7610ed65655d629b93f264adb46ce6d2fb50.
This reverts commit 775e0647a013a0f279fda86f7839e9373707f8ba