DataTable detail and delete API cleanup

[raprasad]

• Format JSON response info
  • [x] JSON response. Flatten field names to first level of JSON dict
  • [x] Change pk to id
  • [x] Remove model
• Detail Tests
  • [x] Detail good
  • [x] Detail non-existent id
• Delete Tests
  • [x] Delete good
  • [x] delete non-existent id

Current JSON:

  {
    "pk": 45, 
    "model": "datatables.datatable", 
    "fields": {
        "uploaded_file": "datatables/boston-income_17.csv", 
        "table_name": "boston_income_17", 
        "title": "boston_income"
    }, 
    "attributes": [
        {
            "attribute": "_unnamed", 
            "type": "int"
        }, 
        {
            "attribute": "fid", 
            "type": "unicode"
        }, 
        {
            "attribute": "objectid", 
            "type": "int"
        }, 
        {
            "attribute": "area", 
            "type": "float"
        }, 
        {
            "attribute": "perimeter", 
            "type": "float"
        }, 
        {
            "attribute": "state", 
            "type": "int"
        }, 
        {
            "attribute": "county", 
            "type": "int"
        }, 
        {
            "attribute": "tract", 
            "type": "unicode"
        }, 
        {
            "attribute": "ct_id", 
            "type": "int"
        }, 
        {
            "attribute": "logrecno", 
            "type": "int"
        }, 
        {
            "attribute": "blk_count", 
            "type": "int"
        }, 
        {
            "attribute": "dry_pct", 
            "type": "float"
        }, 
        {
            "attribute": "dry_acres", 
            "type": "float"
        }, 
        {
            "attribute": "dry_sqmi", 
            "type": "float"
        }, 
        {
            "attribute": "dry_sqkm", 
            "type": "float"
        }, 
        {
            "attribute": "shape_area", 
            "type": "float"
        }, 
        {
            "attribute": "shape_len", 
            "type": "float"
        }, 
        {
            "attribute": "hoods_pd_i", 
            "type": "int"
        }, 
        {
            "attribute": "nbhd", 
            "type": "unicode"
        }, 
        {
            "attribute": "nbhdcrm", 
            "type": "unicode"
        }, 
        {
            "attribute": "nsa_id_1", 
            "type": "unicode"
        }, 
        {
            "attribute": "nsa_name", 
            "type": "unicode"
        }, 
        {
            "attribute": "uniqueid", 
            "type": "int"
        }, 
        {
            "attribute": "uniqueid_1", 
            "type": "int"
        }, 
        {
            "attribute": "ct_id_1", 
            "type": "float"
        }, 
        {
            "attribute": "nbhd_1", 
            "type": "unicode"
        }, 
        {
            "attribute": "b19013_med", 
            "type": "int"
        }, 
        {
            "attribute": "walkabilit", 
            "type": "float"
        }, 
        {
            "attribute": "quality_of", 
            "type": "float"
        }
    ]
}