Fix #57. Never treat a container that is not explictly enabled as a valid inventory.

Unknown containers can do many things that will mess up sorting order, so we should simply ignore them entirely.

Things that want sorting to work should use the API, as long as they follow the basic slot ordering convention they only need the annotations which do not require any runtime dependencies.

Things which need extra handling, or which do not follow the standard/vanilla slot ordering, will require the  ContainerSection enum class file.