initscript: remove all distribution initscripts

initscript: remove all distribution initscripts

These initscripts weren't modified for a long time. Are they just
unused or flawless? It seems they are no longer best-practice
(e.g. NetworkManager supports reloading configuration via SIGHUP,
which none of these scripts implement).

Nowadays some distributions moved to systemd and quite possible
nobody uses these scripts. Also, any potential downstream user
probably has an adjusted copy of them in their repositories.

Just remove them.

https://mail.gnome.org/archives/networkmanager-list/2015-December/msg00003.html