Merge "Add mdns files and unit tests" am: 57852487b8 am: 165cee4902 am: dbbf957240

Original change: https://android-review.googlesource.com/c/platform/packages/modules/Connectivity/+/2098221

Change-Id: I650ad3574d7582873cb5bb3446d507679a4ed2d5
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>