Add a new feature to store IncFs version.

And deprecating the old feature which didn't have versioning support.

V2 means that the new features are either required if the device
was shipped with S, or available if device updated kernel to S.

Bug: 180010901
Test: atest PackageManagerShellCommandTest PackageManagerShellCommandIncrementalTest IncrementalServiceTest PackageManagerServiceTest ChecksumsTest
Change-Id: If037f0eb23260f354b0929ff7afaf1af9627e5fa