logd: enforce policy integrity

If a SELinux policy change or a switch to permissive mode is detected
on a user build, restart the device into safe mode, and keep it there
until an OTA is applied or user data is wiped.

This change deprecates the ro.logd.auditd property.

Needs matching changes from
  I781c3059ea8d4fb2f0c923e4488b1932d69678d3
  Ica825cf2af74f5624cf4091544bd24bb5482dbe7
  Id3ca7889ede30b54b7af73dd50653ca1a20d59aa

Bug: 26902605
Change-Id: Idcdc5bff133f13c1267f0ec0a75cc8cf1ddbda0d
(cherry picked from commit d122ee65)