AOSP: Add "product_available" to product available modules

AOSP: Add "product_available" to product available modules

"vendor_available" modules were available to product modules.
However, not all "vendor_available" modules are required to be
available to product modules. Some modules want to be available only
to product modules but not vendor modules.

To cover the requirement, we separate "product_available" from
"vendor_available".
"vendor_available" will not provide product available module.

Google-Bug-Id: 150902910
Test: build
Change-Id: I316da0d24bde8b6231114aa80841c59547691152
From AOSP commit: df51b0de40581f52c6515f8775ecd84dc4a50bb0