Adding the missing file
During HA and maintenance call different planners (if the original planners are not able to find capacity) which skip some heurestics
This reverts commit d178b25daa484dda44bb34e63cb719d1c3cc1519 and moves
the initialization to the system context, which really where it should have
been from the beginning.
The following types were not setup to discover extensions
com.cloud.network.element.FirewallServiceProvider
com.cloud.network.element.PortForwardingServiceProvider
com.cloud.network.element.StaticNatServiceProvider
com.cloud.network.element.NetworkACLServiceProvider
com.cloud.network.element.LoadBalancingServiceProvider
com.cloud.network.element.Site2SiteVpnServiceProvider
ACS is now comprised of a hierarchy of spring application contexts.
Each plugin can contribute configuration files to add to an existing
module or create it's own module.
Additionally, for the mgmt server, ACS custom AOP is no longer used
and instead we use Spring AOP to manage interceptors.