feat: add `node_network_address_valid_lft` and `node_network_address_preferred_lft` metrics

Such metrics could help detecting DHCP lease not being renewed in-time.

E.g. the values could come from the stats shown by:

$ ip addr show
1: lo: <LOOPBACK,UP,LOWER_UP> mtu 65536 qdisc noqueue state UNKNOWN group default qlen 1000
    link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00
    inet 127.0.0.1/8 scope host lo
       valid_lft forever preferred_lft forever
    inet6 ::1/128 scope host noprefixroute
       valid_lft forever preferred_lft forever
2: ens3: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1460 qdisc mq state UP group default qlen 1000
    link/ether xx:xx:xx:xx:xx:xx brd ff:ff:ff:ff:ff:ff
    altname enp0s3
    inet nn.nn.nn.nn/32 metric 100 scope global dynamic ens3
       valid_lft 68465sec preferred_lft 68465sec
    inet6 xxxx::xxxx:xxxx:xxxx:xxxx/64 scope link
       valid_lft forever preferred_lft forever

..and result in metrics like:

# HELP node_network_address_valid_lft The valid lifetime of an address
# TYPE node_network_address_valid_lft gauge
node_network_address_valid_lft{device="ens3",family="inet"} 68465
node_network_address_valid_lft{device="ens3",family="inet6"} -1
node_network_address_valid_lft{device="lo",family="inet"} -1
node_network_address_valid_lft{device="lo",family="inet6"} -1

# HELP node_network_address_preferred_lft The preferred lifetime of an address
# TYPE node_network_address_preferred_lft gauge
node_network_address_preferred_lft{device="ens3",family="inet"} 68465
node_network_address_preferred_lft{device="ens3",family="inet6"} -1
node_network_address_preferred_lft{device="lo",family="inet"} -1
node_network_address_preferred_lft{device="lo",family="inet6"} -1

Use the ip addr show output in the issue as the reference for address lifetimes, then trace node_exporter's existing network-address collection entry point. Done means exposing both gauge metrics with device and family labels, including the shown -1 representation for forever values.