Implement procsstats data agggregation

Aggregation of procstats data is done to a subset of total possible
process states; this reduces total data footprint.

Change-Id: Ia1528c5ca33bafcb992e34d5fec53156d357b9e1
Test: make, flash (code not yet invoked)
Bug: 145203981
Merged-In: Ia1528c5ca33bafcb992e34d5fec53156d357b9e1
(cherry picked from commit 1651ad3c)