This removes libnm-glib, libnm-glib-vpn, and libnm-util for good.
The it has been replaced with libnm since NetworkManager 1.0, disabled
by default since 1.12 and no up-to-date distributions ship it for years
Removing the libraries allows us to:
* Remove the horrible hacks that were in place to deal with accidental use
of both the new and old library in a single process.
* Relief the translators of maintenance burden of similar yet different
* Get rid of known bad code without chances of ever getting fixed
(libnm-glib/nm-object.c and libnm-glib/nm-object-cache.c)
* Generally lower the footprint of the releases and our workspace
If there are some really really legacy users; they can just build
libnm-glib and friends from the NetworkManager-1.16 distribution. The
D-Bus API is stable and old libnm-glib will keep working forever.