Fixing autoconf and Adding accept_ra

Salt official documentation says ipv6_autoconf is the correct name
but
/usr/lib/python3/dist-packages/salt/templates/debian_ip/debian_eth.jinja
shows autoconf is actually correct. Found accept_ra in there as well

network/defaults.yaml

@@ -34,7 +34,8 @@ Debian:
       - ipv6ipaddr
       - ipv6netmask
       - ipv6gateway
-      - ipv6_autoconf
+      - autoconf
+      - accept_ra
       - mtu 
     def_entries:
       - name: lo