text: add text macros for if UEFI grub checks fail
ui_newt: check if at least one disk has a EFI system partition
only display EFI warning when booted via EFI
only display BIOS warning when not booted via EFI
Revert "format: add vfat support"

This reverts commit 12133c319dae5eb94406899dc6c3e3162b77e2ff.