Add grub and refind back

"rescue/installation actions for {grub,refind} should be run from
within a chroot" is a false statement. See --boot-directory of
grub-install and --root of refind-install. (In the case of grub,
there are people that do not use the ugly grub-mkconfig at all.)
9 jobs for grub_refind in 98 minutes and 6 seconds (queued for 4 seconds)
latest
Status Name Job ID Coverage
  Check
passed check #40301

00:00:26

 
  Build
passed build_long: [baseline iso] #40304
fast-single-thread

00:35:15

passed build_long: [baseline netboot] #40305
fast-single-thread

00:23:36

passed build_long: [releng iso] #40310
fast-single-thread

00:37:16

passed build_long: [releng netboot] #40309
fast-single-thread

00:41:11

passed build_short: [baseline bootstrap] #40302

00:24:58

passed build_short: [releng bootstrap] #40303

00:24:47

failed build_long: [releng iso] #40306
fast-single-thread

01:00:01

failed build_long: [releng netboot] #40307
fast-single-thread

00:06:04