As DhcpElement/VirtualRouterElement/RedundantVirtualRouterElement is decided to
be the service provider of the physical network, this API should be called to
add a new element, with correlated network service provider ID.
Then e.g. ConfigureVirtualRouterElementCmd should be called to configure and
enable the element.
DHCP range, domain name, etc. are the property of network, not virtual router
specific.
The focus of virtual router configuration would on separate enable/disable each
service it provided.
2)Re-apply all existing firewall rules as a part of implement call. TODO: Cleanup all existing rules from the backend (leave them in the DB) as a part of shutdown call
Add configure command for these virtual router based elements. The commands
should be different for different elements.
The context of configuration would be added later.
Since we would introduce a way to specify each service provider in the network
offering, it's better for redundant virtual router as a separate service
provider.
Also isRedundant() flag in the network offering would be removed. Redundant
virtual router temporality won't work from now. Until we're able to add
different network elements/service providers in network_offering.
