listicon_image_tag - don't assume all images are PNGs from 100/
listicon_image_tag - don't assume all images are PNGs from 100/

we need to change some to PNG, but can't change all of them yet

so moving the 100/*.png to every assignment, so that each can be changed separately
(transferred from ManageIQ/manageiq@89cfe0cad20d9a9517a76cc470ed02178b39f9a2)

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