Get list of adHoc inputs required to delivery via custom delivery.
Each input has a name and type in the following format:

```
{
    "name": "variable_name_here", 
    "type": "string"
}
```

Table inputs are defined using the convention below:

```
{
    "name": "table_variable_name",
    "type": "table",
    "columns": [
        {
            "name": "table_column_name",
            "type": "integer"
        }
    ]
}
```