Add template method(s) to check reachability

[AHelper]

Reachability checks in templates adds an unneccessary level of complexity to verify that one container is reachable by another through any number of networks.

• Add whereReachable $containers $target where $target may be a RuntimeContainer or Network and returns all RuntimeContainers that can access $target
• Add reachable $source $target where $source and $target may be a RuntimeContainer or Network and returns a Boolean value.
• Add reachableNetworks $source $target where $source and $target may be a RuntimeContainer or Network and returns an array of Networks of $target that $source can access.
• Verify that the container has ICC enabled (see com.docker.network.bridge.enable_icc)
• Verify that the network has ICC enabled (see --icc)