Run the derive_sdk service

Run this process as early as possible in the boot -- right
after its config has been parsed from the apex. This ensures
the sdk prop is set as early as it can be, should some other
early process need to look at it.

Note: this is unlikely to be the permanent way this gets run,
as it's only needed when apexes update.

Bug: 137191822
Test: boot && adb shell getprop | grep sdk_info
Change-Id: Ia48ef89435ca165333b52d653e3131f71a522747