Update the mesos containerizer to launch per-container I/O switchboards

With the introduction of the new per-container I/O switchboard component, we need to update the mesos containerizer to actually launch one for each container as well as maintain any checkpointed pid information so it can reattach to it on recovery().

As part of this, we will likely move the existing logger logic inside the I/O switchboard and have it own the logger going forward.