Update server-provision config to allow loading subset of services/middleware

[jwsm]

We're proposing a backwards-compatible enhancement to the "server-provisions" feature/config block introduced in https://github.com/BlueOakJS/blueoak-server/pull/87.

In some cases, a container BOS may wish to only include some subset of services or middleware from a provisioned BOS rather than all. In addition, to avoid naming conflicts you would want to be able to give the provisioned service a mapped name.

In the example below:

• The config is backwards compatible (if an element is a string, all services/middleware are provisioned, if an object the config is read)
• In this example, only femaService and emailService are pulled in from provisioned BOS
• emailService is renamed to myEmailService in the container BOS

"server-provisions": [{
  "package": "sfi-esb",
  "services": [
    "femaService",
    "emailService": {
      "mappedName": "myEmailService"
    }
  ],
  "middleware": [
    ...
  ]
}],

[seanpk]

This looks really useful, and provides a solution to one of the concerns that we had with the first implementation: conflicting service and middleware names.

I'd like to suggest a change to the "extended" format, either: "as" instead of "mappedName" or "myEmailService:emailService"

[jwsm]

Thanks. I will work on an implementation.