Expand ip2nets LNet configuration support for IPv6. LNet currently allows specifying network interface configuration using ip2nets YAML syntax. I want to augment the ip2nets "ip-range" to allow specifying either: 1: a single IPv6 address, or 2: an IPv6 net mask. For example:

Single ipv6 address:

ip2nets:
  - net-spec: tcp1
    interfaces:
         0: eth0
    ip-range:
         0: 2601:8c1:c180:2000:1000:1000:1000:cbdd

an IPv6 net mask:

ip2nets:
  - net-spec: tcp1
    interfaces:
         0: eth0
    ip-range:
         0: 2601:8c1:c180:2000:1000:1000:1000:cbdd/125

Note that a single IPv6 address is equivalent to an IPv6 net mask with prefix length /128. When a single IPv6 address is specified then only an interface with that exact address shall be configured. When an IPv6 net mask is specified, than an interface with an IPv6 address within the network shall be configured.