Update diskstats to break out code & data.

This updates both the text-based diskstats and the proto-based diskstats
to both have both an aggregated and line-itemed view of app sizes.
Formerly, the code and data sizes were rolled up into the same category
and now they are separated.

Bug: 63908720
Test: FrameworksServicesTest passes
Change-Id: I1434327ffde6ad1f31243218c5201a80f9725a63