Add overlayPaths to ApplicationInfo

RROs have historically been APK packages. We now have the ability to
generate RROs on-the-fly. These "fabricated" RROs are not APKs.
ApplicationInfo#resourceDirs documentation states that it only contains
paths to packages. To prevent changing the behavior of resourceDirs
until we can deprecate and remove it, a new overlayPaths field has been
added to ApplicationInfo. This new field contains APK overlay paths as
well as non-APK overlay paths.

Bug: 172471315
Test: boot enable/disable overlays and examine overlays working as well
      as package manager dumpsys
Change-Id: I78c5eeef73b7d8bada61edc0f64a12a3cdc1ce16