POST different frames format through API

Hello I’ve noticed that it is possible to add on board only frames of format “custom”, It will be nice to have a possibility to add different formats like “desktop” or “tablet” 

Below is a response body that I receive
```
{
  "type" : "error",
  "code" : "2.0703",
  "context" : {
    "fields" : [ {
      "field" : "data.format",
      "message" : "Unexpected value [desktop], expected one of: [custom]"
    } ]
  },
  "message" : "Invalid parameters",
  "status" : 400
}
```