[ICAT] Better IDS error handling

[mantid-builder]

Original Reporter: Jay Rainey

This ticket is blocks : TRAC8727

Currently, CatalogPublish cancels the algorithm and outputs a custom error message to the user informing them what we '''think''' the problem was.

A better solution is to obtain the JSON body returned in the response from the server and output the content in the format of: code + " :" + message where code and message are JSON properties.

For example, when a 404 occurs the following status and body is returned:

  Status: 404 (not found)
  Body: json response:
  {
    "code"   : "NotFoundException",
    "message":"Datafile[id:43341911] not found."
  }

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Keywords: ICAT

[mantid-builder]

This issue was originally trac ticket 8730