The new package targets have no drawbacks compared to auto live
mount, but the latter has proven difficult and does not match the
normal boot scenario and could potentially panic due to unionfs
being broken beyond repair (kib@'s words in spirit, not mine).

Discussed with: @adschellevis

(cherry picked from commit 80a70ffe)

We don't use this file very often so clamp down the access range
in order to avoid unwanted leakage.

(cherry picked from commit f50e2f58)

(cherry picked from commit f79e2018)

(cherry picked from commit 8d2cf58b)

(cherry picked from commit 603469c6)

(cherry picked from commit 56f3f564)

(cherry picked from commit 46265467)

The two are mutually exclusive.

(cherry picked from commit 174028db)

(cherry picked from commit 77d83631)

(cherry picked from commit 305ba62b)

(cherry picked from commit 05e75ec6)

(cherry picked from commit 34b75c5e)

(cherry picked from commit 8912f909)

(cherry picked from commit 159d2fd2)

(cherry picked from commit bea8906d)

(cherry picked from commit d7122abb)

o When servers are empty, show prefer and noselect as disabled.
o Tighten the config write by using the same code idiom as the
  frontend, which is the safer method.
o Untangle noselect and prefer, ntpd.conf will handle it.

(cherry picked from commit 80eba3c2)

(cherry picked from commit e7723d47)

(cherry picked from commit 7c3b9959)

(cherry picked from commit cdb17e69)

(cherry picked from commit 0ede7b89)

(cherry picked from commit e6173b4b)

(cherry picked from commit f4b773de)

(cherry picked from commit 9871f0ba)

(cherry picked from commit de12c9fa)

(cherry picked from commit a352d3a8)

(cherry picked from commit 20e1e495)

(cherry picked from commit 527773d7)

(cherry picked from commit f4fcce27)

(cherry picked from commit 4a973535)

(cherry picked from commit fe2c4e0b)

(cherry picked from commit 875d5761)

(cherry picked from commit 6e7f1432)

(cherry picked from commit a8006f27)

(cherry picked from commit 67b827a8)

(cherry picked from commit a1a8129f)

(cherry picked from commit 52a1fc2a)

(cherry picked from commit 9b18fb80)

(cherry picked from commit 59504c5c)