[DisplayEventDispatcher] Kick DisplayEventDispatcher out of libandroidfw.

DisplayEventDispatcher will live in libgui for now, as a shim over
DisplayEventReceiver. This is so that we can keep libgui out of the
UI-renderer module while we can work on stabilizing the interface with
libandroidfw for asset management required by graphics classes.

It also doesn't make much sense to have display-event functionality in a
separate grab-bag library, especially when there's two users, and
there is potentially an opportunity to somehow merge with
DisplayEventReceiver to simplify code a bit.

Change-Id: Ife0f9c8ad2053437087fdbf0618b892928ce6864
Bug: 142760698
Test: builds