Remove SELF references in Component Orchestrator config

[weberjm]

In the Orchestrator config YAML files, there is a field called SELF_URL, which is not used anywhere in the application. The Orchestrator DOES, however, call to a key called SELF_API_URI, which is not set in the Web-UI config, but gets passed to node containers, and is also the key declared in the README file for the service.

According to @heggert, the Orchestrator now manages every step within a flow by itself, making these keys dispensable. There is no reason to request a specific "stepInfo" via HTTP anymore. We can nowremove every reference and assignment to SELF_API_URI.