Bluetooth: Mesh: add more fixed group addresses

Mesh-1.1 spec extends number group addresses.
There were added:
all forwarding address,
all ip nodes,
all ip border routers.
Even Zephyr's mesh doesn't support them it should be able
to subscribe heartbeat on these groups.
Also mesh should provide ability to subscribe\publish models on
these groups.

Signed-off-by: Aleksandr Khromykh <aleksandr.khromykh@nordicsemi.no>