Codesigns and notarizes the package. Requires a bunch of stuff to
actually get this working. (see contrib/macos-signing.txt).
I'm currently also building with
-DLOKINET_GUI_REPO=https://github.com/jagerman/loki-network-control-panel.git -DLOKINET_GUI_CHECKOUT=cmake
because it needs the camke-ification PR for the control panel to
properly sign everything there.