Wiki instructions for adding a node is missing a step

[dthaler]

https://github.com/orcasound/orcanode/wiki/Administration-of-network-nodes#set-up-a-new-node-in-the-orcasound-hydrophone-network
is missing a step.

On the AWS console, an API key must be created with group membership in nodes-dev (for a dev node) or nodes-prod (for a prod node).