This shows the name of the app, the runtime in use and the permissions
that the app has. This is useful for a client to know if e.g. it needs
to use a portal of some sort.
These point to the per-app data subdirectories. They are useful alternatives
to the $HOME based names because they have fixed names, and can be used
in e.g. symlinks.
This moves a all source code into separate subdirs per binary. The
helper and the generic stuff goes into lib/ which is then used by all
the others. For now this is a completely internal library, but at
some point we will probably clean it up and expose some subset.
Also, we move the dbus proxy to libexecdir.