Remove model_name.* keys from en.yml
Remove model_name.* keys from en.yml

The intention behind model_name.* keys was to use these values
in miq_policy_controller, but for it to work, these keys would
have to be all under 'dictionary' tree.

In the end, these values are not needed at all. We can safely
use ui_lookup(:model => ...) instead.
(transferred from ManageIQ/manageiq@8c6e91ac6af0fd7ca797a39a89d6e9089ed36449)

ManageIQ/manageiq-ui-classic,ManageIQ/manageiq-ui-classic,ManageIQ/manageiq-ui-classic,ManageIQ/manageiq-ui-classic