Support to install prebuilt split APKs with LOCAL_PACKAGE_SPLITS

In prebuilt app module, you can use LOCAL_PACKAGE_SPLITS to specify a
list of prebuilt split apks. The build system will sign and zipalign the
apks and install them with the same file names.
Note that you need to put all the source split apks in the same folder.

Bug: 16319961
Change-Id: Id2b6d743c1edc5e436007ec11acece1748adad45