Simplify our Translator Entity UI once these features are available in the Entity API

I just posted the patch for that over at the Entity API issue queue.

@see these issues:

• #1439400: Provide enabled/disabled state handling
• #1437272: Provide a description entity key especially for use with exportable entites (e.g. as seen in node types)
• #1437258: Provide a weight entity key for sorting exportable entities (e.g. with a tabledrag).