Chg: User: Initial commit of JSON load code for gh-222

Example in tests/house.json
if using dev build of ank:

```
$ autonetkit -f tests/house.json
INFO VIRL Configuration Engine 0.9.0
INFO AutoNetkit 0.9.0
INFO IPv4 allocations: Infrastructure: 10.0.0.0/8, Loopback:
192.168.0.0/22
INFO Allocating v4 Infrastructure IPs
INFO Allocating v4 Primary Host loopback IPs
INFO Topology not created for VIRL, skipping Cisco PCE design rules
INFO Skipping iBGP for iBGP disabled nodes: []
INFO All validation tests passed.
INFO Rendering Configuration Files
INFO Finished
```

if run in monitor mode, then changes will be reflected live:
```
$ ank_webserver
```

and then
```
$ autonetkit -f tests/house.json —monitor
```