Add more target-specific properties

Following properties are added:

* vendor.header_libs
* platform.cflags
* platform.header_libs
* platform.exclude_shared_libs

These are used in the *-ndk libraries generated from the aidl_interface
modules, so that we can build the platform variants of the libraries
just like the *-ndk_platform libraries. Eventually, we will remove the
*-ndk_platform libraries.

Bug: 161456198
Test: m
Change-Id: Ie54b512a6769b3c4c60815b5eeabb4f52263498e