Add the scope of found ipv6 addresses (global/linklocal/...) as a fact

Puppet Version: any
Puppet Server Version: any
OS Name/Version: any

For certain configuration tasks, it is important to know not only if a host has an IPv6 address (networking.ip6 is not empty), but also if that address is a globally routable address or a link-local address. 

Desired Behavior:

**facter returns the scope for the ip6 address it finds: 

$ facter -p networking.ip6

2001:4860:4860::8888

$ facter -p networking.ip6_scope

global

$ facter -p networking.ip6

fe80::a800:ff:fe63:14d5

$ facter -p networking.ip6_scope

link

Actual Behavior:

networking.ip6_scope does not exist.

The scope information can be derived from the output of ip:

ip -6 a l dev eth0

2: eth0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 state UP qlen 1000

    inet6 fe80::a800:ff:fe63:14d5/64 **scope link**  <--- 

       valid_lft forever preferred_lft forever