UpdateResource query action

[aaron-collier]

Query Resource (ID, Version) from Metadata Persistence Layer

• [ ] Query DynamoDB resources table for id == ID && currentVersion == true
• [x] If no records are returned from Dynamo return a "Resource Not Found" error to client
• [x] if a record is found from Dynamo:
  • [x] Save response map[string]*dynamoAttribute to GenericResource map (i.e. map[string]interface{})
  • [x] Return GenericResource to ExistingResource

Reference https://github.com/sul-dlss-labs/taco/wiki/TACO-Internal-Processing-Steps#update-resource