dnsmasq: change 'add_local_hostname' to use dnsmasq '--interface-name'

dnsmasq: change 'add_local_hostname' to use dnsmasq '--interface-name'

'add_local_hostname' previous implementation may drop some addresses.
Soft addition of IP6 addresses may not cause a reload or restart event.
dnsmasq '--interface-name' robustly applies DNS to all addresses per
interface (except fe80::/10).

Change UCI 'add_local_hostname' to expand during each interface assignement
during add_dhcp().
Assign '<iface>.<host>.<domain>' as true name (reflexive A, AAAA, and PTR).
Assign '<host>.<domain>' and '<host>' as convinience aliases (no PTR, not
technically CNAME).
This is accomplished with the '--interface-name' order, first is PTR.
We could also assign each <ip4/6>.<iface>.<host>.<domain> to the respective
dual stack on the interface.
That seemed excessive so it was skipped (/4 or /6 suffix to the interface).
Add UCI 'add_wan_hostname' similar to 'add_local_hostname' function for
external WAN.

WAN IP4 are less often named by the ISP and rarely WAN IP6 due to complexity.
For logs, LuCI connection graph, and other uses assigning a WAN name is desired.
'add_local_hostname' only applies with DHCP and 'add_wam_hostname' only applies
without DHCP. Common residential users will want to set both options TRUE.
Businesses will probably have global DNS, static IP, and 'add_wan_hostname' FALSE.

Signed-off-by: Eric Luehrsen <ericluehrsen@hotmail.com>