Change Ghaf internal network IP address range to less risky with conflicts

[vilvo]

          > Today I had a routing problem in Ghaf, because my default internet router subnet is 192.168.101.0/24.

[ghaf@net-vm:~]$ route
Kernel IP routing table
Destination     Gateway         Genmask         Flags Metric Ref    Use Iface
default         net-vm          0.0.0.0         UG    1025   0        0 wlp0s4f0
192.168.100.0   0.0.0.0         255.255.255.0   U     0      0        0 ethint0
192.168.101.0   0.0.0.0         255.255.255.0   U     0      0        0 ethint0
192.168.101.0   0.0.0.0         255.255.255.0   U     1025   0        0 wlp0s4f0
net-vm          0.0.0.0         255.255.255.255 UH    1025   0        0 wlp0s4f0

The problem was that the net-vm was not able to ping my laptop because the default route in that case was through ethint0 and not to wlp0s4f0.

The solution in my case was simple, change the subnet in my Internet router to 192.168.110.0. But, many user could have a similar problem if their Internet routers subnet are 192.168.100.0 or 192.168.101.0. I think that the subnet managed by the net-vm should be one less popular, such as 192.168.170.0/

@jpruiz84 This is good suggestion. However, I left the change of the ghaf subnet ip addresses now out of this PR because it can cause some confusion in development and breaks in testing (when they have relied on IP addresses when the internal host name queries did not work). Now that the internal host name queries work, let's give people in development and testing time to adopt the change. Then the IP address range can be changed to something less likely to conflict.

Originally posted by @vilvo in #427 (comment)