Create separate packages for the VPN plugins. Each plugin has the .so
library and necessary script along LICENCE file.
Also add vpn-script, openvpn-script and libppp-plugin.la into separate
vpn-scripts package. Every VPN plugin needs these files. vpn-script is
needed by OpenConnect and VPNC. libppp-plugin.la is needed by L2TP and
PPTP. Because the directory is owned by the connman-vpn-scripts package
it makes sense to have all scripts in one package to get the directory
properly removed when packages are removed.