Ebo feature 5535

If you want to display this feature in a view, you must add the following lines:

```xml
<!-- Inside HTML head node -->
<view:includePlugin name="lang" />

<!-- Inside HTML body node -->
<div id="lang-select-div"></div>
```
I have changed some code in order to respect comments from https://github.com/Silverpeas/Silverpeas-Core/pull/517