Merge pull request #8252 from miri64/gnrc_netif/api/rename-ipv6_addr

sys/include/net/gnrc/netif/internal.h

sys/net/gnrc/netif/gnrc_netif.c

sys/net/gnrc/network_layer/ipv6/nib/_nib-6ln.c

sys/net/gnrc/network_layer/ipv6/nib/_nib-router.h

sys/net/gnrc/network_layer/ipv6/nib/nib.c

sys/net/gnrc/routing/rpl/gnrc_rpl.c

sys/net/gnrc/routing/rpl/gnrc_rpl_control_messages.c

tests/gnrc_ipv6_nib/main.c

tests/gnrc_ipv6_nib_6ln/main.c

tests/gnrc_netif/main.c