Add support for forward/reverse DNS range split

- Allow for explicit reverse RFC1918 lookups with unbound_reverse_zones
- Add tests, similar to NSD ones
- Wait for network to be online before starting (fixes AETHER-1041)
- Multiplatform support

Change-Id: I385aec6f766b45a9db595d2f8af5ed8fe0dde2ca
11 files changed