Warn when running activity from deprecated app (< min supported sdk).

As part of deprecation policy enforcement for android apps, minimum
supported targetSdkVersion will be 17. Apks targeting values lower that
one set in PLATFORM_MIN_SUPPORTED_TARGET_SDK_VERSION (currently set to 0)
will display a dismissible warning when run.

More info can be found in go/android-targetsdkversion-warning

+ Fix in AppWarnings.setPackageFlag, "enable" logic was wrong way around
('false' was setting the flag and 'true' clearing it)
+ Added FLAG_ACTIVITY_NEW_TASK to AppInstallerUtil.createIntent
result, otherwise it will crash system server when startActivity is
called without this flag.

Test: atest CtsActivityManagerDeviceTestCases:DeprecatedTargetSdkTest
Bug: 63926630
Change-Id: I93e0079af763a97ee47b3d8212648d422bc6614d