New public API to get the information of AndroidManifest.xml

Define a public API of PackageManager to get the information of
AndroidManifest.xml file for the base apk and split apks.

Bug: 269149275
Bug:308860376
Test: atest CtsPackageManagerTestCases
Change-Id: Ic4fdc9edbd3248d55229a56d5649dcad4d835667