/proc, /sys access from uncrypt, update_engine, postinstall_dexopt

New types:
1. proc_random
2. sysfs_dt_firmware_android

Labeled:
1. /proc/sys/kernel/random as proc_random.
2. /sys/firmware/devicetree/base/firmware/android/{compatible, fstab,
vbmeta} as sysfs_dt_firmware_android.

Changed access:
1. uncrypt, update_engine, postinstall_dexopt have access to generic proc
and sysfs labels removed.
2. appropriate permissions were added to uncrypt, update_engine,
update_engine_common, postinstall_dexopt.

Bug: 67416435
Bug: 67416336
Test: fake ota go/manual-ab-ota runs without denials
Test: adb sideload runs without denials to new types
Change-Id: Id31310ceb151a18652fcbb58037a0b90c1f6505a