Add support for credentials in msg.
Add support for credentials in msg.

This makes the node stateless with respect to users.

node-red/node-red-web-nodes,mblackstock/node-red-web-nodes,node-red/node-red-web-nodes,mblackstock/node-red-web-nodes,SenseTecnic/node-red-web-nodes,drwoods/node-red-web-nodes,drwoods/node-red-web-nodes,SenseTecnic/node-red-web-nodes