Dynamically specified API credentials

[wloody54]

Set Credentials programmatically [GOT CREATED]

Did just add full expression support to credentials: That allows now to use any kind of flow data in credentials. The only limitation is that it uses always the data of the first item. So if there are two items the first one having name: frank1, the second name: tom2 and credentials using the following expression {{$json.name}} it would use in the credentials only the value frank1.