k_queue: allow user mode access via allocators

User mode may now use queue objects. Instead of embedding the kernel's
linked list information directly in the data item, a container struct
is allocated from the caller's resource pool which is then added to
the queue. The new sflist type is now used to store a flag indicating
whether a data item needs to be freed when removed from the queue.

FIFO/LIFOs are derived from k_queues and have had allocator functions
added.

Signed-off-by: Andrew Boie <andrew.p.boie@intel.com>