packaging: ship render worker on Linux, ffmpeg_bridge.dll on Windows

- Linux: olive-render-worker had no install rule, so it was missing
  from the AppImage, deb, rpm and Arch packages even though
  RenderWorkerPool spawns it from applicationDirPath(); install it next
  to oak-editor (verified: RPATH resolution of libffmpeg_bridge works
  for editor, worker and liboakgl from the installed layout)
- Windows: ffmpeg_bridge.dll is built outside app/ and is invisible to
  the ntldd dependency walk, so the NSIS installer shipped without it
  (and without the av*.dll it pulls in); copy it explicitly and include
  it in the dependency loop
- AppImage verification now also checks oak-render-worker, liboakgl.so,
  libffmpeg_bridge.so and ldd resolution of all shipped binaries

app/CMakeLists.txt

@@ -331,7 +331,9 @@ elseif (APPLE)
     endif ()
 elseif (UNIX)
     # Set Linux-specific properties for application
-    install(TARGETS olive-editor RUNTIME DESTINATION bin)
+    # The render worker must ship next to oak-editor: RenderWorkerPool spawns
+    # it from QCoreApplication::applicationDirPath()
+    install(TARGETS olive-editor olive-render-worker RUNTIME DESTINATION bin)
 endif ()
 
 # Set link libraries