Use strict data type for "ipv" parameter.

Only show IP version selector if more then one is available.

Don't show IPv6 in the list if IPv6 is disabled.

Use alterator-service-functions.

ipv6: Don't enable dhcpd6 is radvd is not installed.
ipv6: Show error if radvd is not installed.
ipv6: Start/stop radvd simultaneously with dhcpd6.
alterator-dhcp-reset: Generate radvd.conf in case of IPv6

ipv6: Use hostname as host identifier in the dhcpd6.conf.
ipv6: Fix 'static' page.
Fix get_static_conf().

Initial DHCPv6 support.

lost changes from previous release

don't use ddns if SERVER_ROLE not master

make it usable without ddns

improve address range check (use modern functions from alterator-net-functions)
add postinstall hook
backend: use run_localized() to write local date

update dhcp config before server start (closes: #21095)

ui: use workflow 'none'
dhcp backend:

improve static binding (add cleanup of dhcp leases)

introduce `altlinux' option space (sbolshakov@)
call kdc hook if exists during per-host dhcp option create (sbolshakov@)

start daemon after config update