The current configuration for dhcp-server is messy.
Replace `boolean` parameter from the folowing nodes and make it valueless. This requires a migration script which is tracked with this task
* `set service dhcp-server shared-network-name <xyz> subnet 172.31.0.0/24 ip-forwarding enable (true|false)`
* `set service dhcp-server shared-network-name <xyz> authoritative (true|false)`
* `set service dhcp-server disabled (true|false)`
In addition replace the nested start/stop ip address from
* `set service dhcp-server shared-network-name <xyz> subnet 172.31.0.0/24 start 172.31.0.101 stop 172.31.0.149`
with something non nested like we already have for l2tp vpn
```
cpo@LR1# show service dhcp-server shared-network-name <xyz> subnet 172.31.0.0/24
default-router 172.31.0.254
dns-server 172.31.0.254
domain-name mybll.net
lease 86400
client-ip-pool {
start 172.31.0.101
stop 172.31.0.149
}
```
... suggestions welcome ...
Details:
* If `set service dhcp-server shared-network-name <xyz> subnet 172.31.0.0/24 ip-forwarding enable false` is set, the whole node will be deleted, converting it to positive logic
* If `set service dhcp-server shared-network-name <xyz> authoritative false` is set, the whole node will be deleted, converting it to positive logic
* If `set service dhcp-server disabled false` is set, the whole node will be deleted, converting it to positive logic