Extract the os specific snapshot module properties handling

Previously, the code was inlined in the addSnapshotModule() method
which made it difficult to follow, did not have clear separation
between the different pieces and duplicated functionality. This
change combines the dynamic and static properties together and then
separates the processing into collation, optimization and property
set updating methods.

Bug: 186290299
Test: m nothing
Change-Id: I311eebca2337cb67634e63d71da12305f4370c07