Use SRX firewall filter as SRX firewall. The old security policy mechanism
cannot be used as IP based. This would enable SRX's ability to control traffic
for F5 behind it.
-made Netscaler, SRX, F5 network elements as pluggable service
-added abstract load balancer device manager ExternaLoadBalancerDeviceManager
-made both F5 and Netscaler pluggable service to extend ExternaLoadBalancerDeviceManager
-added abstract firewall device manager ExternalFirewallDeviceManager
-made SRX pluugable service to extende ExternalFirewallDeviceManager
-added API's to configure and manage netscaler devices