Support complete job config overlay files.

[ddebrunner]

JobConfig provides a logical view of the job config overlay and provides the ability to add in raw overlay information. This is used by streamsx-runner and Topology submission.

However the output of the Topology submission is a JSON file containing the complete overlay, this currently cannot be used by either submission method. In addition complete files may exist for existing SPL projects.

So if one builds a bundle using BUNDLE context, you cannot use the resultant job config overlay JSON as-is on a subsequent streamsx-runner invocation.

Proposing:

• [x] Add support for a comment (#1532)
• [x] Add method to get the full overlay (#1532)
• [x] Static methods in JobConfig to create an instance from a file or dict. (#1534)
• [x] Addition arguments to streamsx-runner to fully support job config overlays. (#1547)
• [ ] Support raw overlay additions with streamsx-runner
• [ ] Update streamsx-runner doc page.

Ref: https://www.ibm.com/support/knowledgecenter/en/SSCRJU_4.2.1/com.ibm.streams.ref.doc/doc/submitjobparameters.html

[markheger]

• same feature set as streamsx-streamtool submitjob
• documentation describes job-config-overlays