New Credentials Setter Node

[chughts]

Create a new node to set credentials for each of the Watson Services. Allowing for some of the services not to have credentials set.

Node will have no inputs and no outputs. On dialog save the node should put the credentials on the global context. Then modify service-utils to check the global context should nothing be found on vcap, and make the credentials available.

As all the Nodes for active services already use service-utils they will automatically be able to detect if credentials have been placed in the global context, make use them and not prompt for the credentials.