Changes similiar item search API to support array of values

[jocki]

Current API only support a single value such as:

{
   "fields": ["name", "description", "category"],
   "value": "{put the name} {put the description} {put the category}"
}

Rather than putting the values as one single concatenated string (use case: one textbox search all fields), it is better to support different values for each fields, such as:

{
   "fields": ["name", "description", "category"],
   "value": ["{put the name}",  "{put the description}",  "{put the category}"]
}