workqueue: Remove module param disable_numa and sysfs knobs pool_ids and numa

Unbound workqueue CPU affinity is going to receive an overhaul and the NUMA
specific knobs won't make sense anymore. Remove them. Also, the pool_ids
knob was used for debugging and not really meaningful given that there is no
visibility into the pools associated with those IDs. Remove it too. A future
patch will improve overall visibility.

Signed-off-by: Tejun Heo <tj@kernel.org>