Add warning/error handling to DCATUS writer for required properties.

[rshewitt]

User Story

In order to correctly process information according to the DCATUS schema, datagov wants to add warning/error handling to the DCATUS writer for required properties

Acceptance Criteria

[ACs should be clearly demoable/verifiable whenever possible. Try specifying them using BDD.]

• [ ] GIVEN the DCATUS writer
  AND the v1.1 schema WHEN a required property is missing
  THEN the writer fails to process
  AND the error/warning is appended to the writer messages array.

Background

• the DCATUS writer doesn't check for required properties which is a standard practice for MDTranslator reader/writers. these checks need to be added.

Security Considerations (required)

[Any security concerns that might be implicated in the change. "None" is OK, just be explicit here!]

Sketch

• dcatus v1.1 schema doc
• for all required properties add a check in the associated module to handle when the property is nil/empty. for example, title is required. if that value doesn't exist then handle it like...

  # ...
  metadataInfo = intObj[:metadata][:metadataInfo]
  resourceInfo = intObj[:metadata][:resourceInfo]
  citation = resourceInfo[:citation]
  
  title = citation[:title]
  if title.nil? 
    responseObj[:writerPass] = false
    responseObj[:writerMessages] << "title is missing"
    return 
  end
  # ...