Log the temp allowlist reason/duration at FGS start.

There are four ways a package can be temp allowlisted:
1. Calling BroadcastOptions#setTemporaryAppWhitelistDuration() to
allowlist a BroadcastReceiver, this is a SystemApi.
2. Calling ActivityManagerService#setPendingIntentWhitelistDuration()
to allowlist a PendingIntent, this is not an API, it is an internal method.
3. Calling PowerWhitelistManager#whitelistAppTemporarily() to allowlist
a package, this is a SystemApi.
4. DeviceIdleController.addPowerSaveTempWhitelistApp(), this is an
internal method.

Also the package can be permanently allowlsited in
 ActivityManagerService#mDeviceIdleExceptIdleAllowlist.

Move the BG-FGS-launch reasonCode from ActiveService.java to
PowerWhitelistManager.java. Define a list of temp allowlist reasonCode
in addition to the BG-FGS-launch reasonCode. The reasonCode is passed
around in DeviceIdleController and ActivityManagerService, it will be
used in statsd FGS metric.

At FGS start, check all above allowlists and record the reasonCode/reason/duration in
ServiceRecord#mInfoTempAllowListReason field.

If mInfoTempAllowListReason is not null, log the reasonCode/reason/duration in "Background started FGS" log
message, with key "tempAllowListReason".

Bug: 171305836
Test: atest cts/tests/app/src/android/app/cts/ActivityManagerFgsBgStartTest.java
Reboot device, observe all "tempAllowListReason" listed above in logcat.
BYPASS_INCLUSIVE_LANGUAGE_REASON=existing APIs

Change-Id: Ieb52d95aae3258817a67734c093cb12fc78a81fd
CTS-Coverage-Bug: 181160445