Hash table implementation && slab_alloc/slab_free hooks && call ktsan_init on boot

move them to ktsan.c, use ENTER/LEAVE
then add internal kt_malloc/kt_free functions, they must accept thr/pc, they must not know about kmem_cache as they can be used for user calls of pagealloc as well
internal function just need to know that this block of memory was allocated/freed by this thread