[set/map/vector] Make constructable, but not copy or assignable

Disable copy/assign on them, as they shouldn't.

Make constructor / destructor call init_shallow/fini_shallow,
and make those idempotent.  So, these three can be constructed
on stack now and no init/fini call is needed.  As such,
hb_auto_t<> is not needed anymore.  I'll remove that separately.