feat: Add grid breakpoint css_variables
feat: Add grid breakpoint css_variables

So that other apps does not have to be dependant on 'variables' file to get grid sizes

mhbu50/frappe,saurabh6790/frappe,StrellaGroup/frappe,almeidapaulopt/frappe,yashodhank/frappe,saurabh6790/frappe,yashodhank/frappe,mhbu50/frappe,almeidapaulopt/frappe,frappe/frappe,saurabh6790/frappe,yashodhank/frappe,mhbu50/frappe,saurabh6790/frappe,almeidapaulopt/frappe,StrellaGroup/frappe,mhbu50/frappe,yashodhank/frappe,StrellaGroup/frappe,almeidapaulopt/frappe,frappe/frappe,frappe/frappe