The "shared" directory contains files that are possibly used by all components
of NetworkManager repository.

Some of these files are even copied as-is to other projects (VPN plugins, nm-applet)
and used there without modification. Move those files to a separate directory.
By moving them to a common directory, it is clearer that they belong
together. Also, you can easier compare the copied versions to their
original via

  $ diff -r ./shared/nm-utils/ /path/to/nm-vpn-plugin/shared/nm-utils/