Move EditorController initialization into attachedCallback
Move EditorController initialization into attachedCallback

Works around a buggy interaction between Turbolinks and Chrome's native custom elements implementation, where cloning the unattached editor results in its value attribute being lost. Needs further investigation.

GabiGrin/trix,GabiGrin/trix,basecamp/trix,ChenMichael/trix,urossmolnik/trix,basecamp/trix,basecamp/trix,ChenMichael/trix,GabiGrin/trix,urossmolnik/trix,basecamp/trix,urossmolnik/trix,ChenMichael/trix