Allow use of delimited_root_name for JSON

When importing delimited text data to generate JSON, an input like this:

key1,key2,key3,key4
a,b,c,d
e,f,g,h

will produce JSON like this:

{
  "key1": "a", 
  "key2": "b", 
  "key3": "c", 
  "key4": "d"
}

Allow the use of -delimited_root_name for JSON to set a root property.

mlcp.sh import -username admin -password admin -host localhost -port 8000 -input_file_path test.csv -document_type json -input_file_type delimited_text -delimited_root_name myRoot

producing:

{
  "myRoot": {
    "key1": "a", 
    "key2": "b", 
    "key3": "c", 
    "key4": "d"
  }
}

(Issue filed in response to a Stack Overflow question.)