Add support for reporting product components to Omaha.

Parse the product_components file from os-release.d and report
them in separate xml attributes.

Bug: 67872115
Test: check omaha request
Change-Id: I82cc3ef30b0cc9bab33f8e7eb939856a4740b9e3
(cherry picked from commit a025114f8df6509f80e60b19b5eca615610104b1)