Implement resource for record metadata

[ghost]

Definition

Currently the record metadata is stored a single document in the database. This will cause problems with blobs producing a large amount or records (Host-component records bundles in Melinda).

Changes

• Records metadata should be stored within another collection
  • Metadata should include successfully transformed records and failed records as well
• Blob metadata should have a the following new properties for:
  • Number of successfully processed records
  • Number of failed records
  • Total number of processed records
• There should be resource to retrieve records metadata, e.g. GET /blobs/:id/results
  • The payload should be streamed to clients (See readContent)