Create build rules for hermetic .img files

Make packaging generates build rules for two $partition.img files
1. Containing inodes with build timestamps
2. Containing inodes with pinned timestamps

The former is useful for adb sync. The latter is used for
target_files.zip.

This CL creates a build rule to generate (2) with soong `filesystem` modules.
The propFile for (2) will be created by concat'ing the propFile for (1)
with `use_fixed_timestamp=true`

Test: m out/soong/.intermediates/build/soong/fsgen/aosp_cf_x86_64_phone_generated_device/android_x86_64_silvermont/target_files.zip out/target/product/vsoc_x86_64/obj/PACKAGING/target_files_intermediates/aosp_cf_x86_64_phone-target_files.zip
Test: diff -r out/target/product/vsoc_x86_64/obj/PACKAGING/target_files_intermediates/aosp_cf_x86_64_phone-target_files/ out/soong/.intermediates/build/soong/fsgen/aosp_cf_x86_64_phone_generated_device/android_x86_64_silvermont/target_files_dir/ --no-dereference
- super_empty.img and system_other.img are missing
- vbmeta*, boot* and userdata have binary diffs
- the rest are identical

Change-Id: If078220f215693660796090eb9b690b0ad41fd38