Create a Life cycle Manager

[OZiad]

The life cycle manager node is responsible for transitioning the life cycle nodes through the life cycle states

[Nicaus]

I think this already exists with the service_client node, if you look at the function void callee_script, it makes it so concerned nodes in launch files get to be managed, if you want it be more specific for each nodes, it can be done with service_client.
Maybe a name change would be appropriate

[OZiad]

hmm yea thanks for the heads up, definitely needs a rename but this should make things a lot easier. gonna leave issue up for now.