Add dumpsys entry point for package storageStats.

Flag: android.content.pm.Flags.get_package_storage_stats
Bug:332905331

Test: adb shell pm get-package-storage-stats  com.google.android.youtube
sample output:
code: 151909888 bytes (144.87 Mb)
data: 8081408 bytes (7.71 Mb)
cache: 6602752 bytes (6.30 Mb)
apk: 110509971 bytes (105.39 Mb)
lib: 0 bytes
dm: 1282352 bytes (1.22 Mb)
dexopt artifacts: 40149956 bytes (38.29 Mb)
current profile : 18094 bytes (17.67 Kb)
reference profile: 98524 bytes (96.21 Kb)
external cache: 6279168 bytes (5.99 Mb)

Change-Id: I19083664f29756f3e3918de74d48b44b81a254dc