feat(ngPluralize): add support for bind-once in `count`

The 1st commit contains the change and test for adding support for `bindOnce` in `count`.
The 2nd commit contains some nimor refactoring (mainly to avoid repetitive actions).

Closes #10004
(Makes #5452 obsolete)
i don't care a whole lot about that --- @petebacondarwin would you be pro-refactoring forEach?