BatchAction pluralization never counts the items

Looking more closely at BatchAction it seems that it never really counts the number of items are the passed in. Instead it will choose a translations based on either the number 1 (if no items are passed in), or the number 6 (because that's the number of letters in 'plural').

For some languages, like Russian, and I think Polish, there should be different translations used for describing 2 or 6 items.

We should make sure that when there is a known number of items we use that in the BatchAction lookups. We probably shouldn't have _any_ references to singular and plural in the code once this is done.

I'm looking at
horizon/tables/actions.py
def _get_action_name(self, items=None, past=False):

and the calls to it like
self.verbose_name_plural = kwargs.get(
'verbose_name_plural',
lambda: self._get_action_name('plural'))

and especially the call in update
 self.verbose_name_plural = self._get_action_name('plural')