Converter: Separate Dom->Model and Model->Dom conversion into separate classes

Leave the methods in the same file to make code review easier.

Change-Id: I4169ccd9ad126f0404966c5daf113e84e03fb678

Author: edg2s

src/ce/ve.ce.TextState.js

@@ -400,7 +400,7 @@ ve.ce.TextState.prototype.getChangeTransaction = function ( prev, modelDoc, mode
 						continue;
 					}
 					ann = ve.dm.annotationFactory.createFromElement(
-						modelClass.static.toDataElement( [ element ], ve.dm.converter )
+						modelClass.static.toDataElement( [ element ], ve.dm.converter.modelFromDomConverter )
 					);
 					const oldAnn = oldAnnotations.getComparable( ann );
 					if ( oldAnn ) {