Migrate textArea widget types to be enhanced with code mirror

Since Studio uses code mirror, we need to be able to distinguish which widget will be rendered with code mirror.

Currrently, all widget of type 'textArea' are rendered with code mirror along with javascript mode by default.

We want to easily be able to tell whether a textArea must be rendered with code mirror and with which mode.

To do so, we'll introduce a new widget type called 'codeArea' and a widget property called 'language' which will determine which mode must be applied by code mirror:

• javascript
• css
• xml
• nxql
• ...
  The widget/layout engine will be able to fall back on a regular html text area in the JSF UI (showcase).

Finally, the new 'codeArea' widget type will also have the following properties:

• columns
• lines