userspace: get dynamic objs from thread rsrc pools

Dynamic kernel objects no longer is hard-coded to use the kernel
heap. Instead, objects will now be drawn from the calling thread's
resource pool.

Since we now have a reference counting mechanism, if an object
loses all its references and it was dynamically allocated, it will
be automatically freed.

A parallel dlist is added for efficient iteration over the set of
all dynamic objects, allowing deletion during iteration.

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