Add configs for cassandra3.staging

Refs. sysadm-environment#4808

configs/cassandra3.yaml

+---
+VLAN_ID: 443
+IPADDRESS: 192.168.130.183
+NETMASK: 255.255.255.0
+GATEWAY: 192.168.130.1
+NAMESERVER: 192.168.100.29
+HOSTNAME: cassandra2
+DOMAINNAME: internal.staging.swh.network
+DEPLOYMENT: staging
+SUBNET: sesi_rocquencourt_staging
+BOOT_DISK_ID_PATTERN: "*_Boot_Controller_*"