fixes #3693 - API v2 - accept GET json format of object in PUT/POST requests to add/remove has_many associations

Currently we have to use _ids= methods to add/remove relationships.
 ```
{
  "id": 42,
  "name": "CentOS",
  "architecture_ids": [1,2]
}
```
This is what we want 
```
{
  "id": 42,
  "name": "CentOS",
  "architectures": [ 
        {
        "id": 1,
        "name": "i386" 
         }, 
        {
         "id": 2,
         "name": "x86_64" 
         }
     ]
}
```
This DOES NOT update the associated objects (architectures).  It's only for adding/removing relationships

If "id" is NOT present and "name" is, then it can add/remove relationships by name

```
{
  "id": 42,
  "name": "CentOS",
  "architectures": [ 
        {
        "name": "i386" 
         }, 
        {
         "name": "x86_64" 
         }
     ]
}
```