Add a configuration point for the webanalytics provider and token

Add the possibility to manage provider and token in webanalytics without configuring it in page or by a property file.
- webanalytics.provider to setup a global provider
- webanalytics.token to setup a global provider
In JSP, all attributes became optional
In Thymeleaf, all attributes became optional and a new attribute has been added to enable the webanalytics tracker.
<html wa:tracker=" token | all "/>
* all : all points needs to be configured,
* token : only the provider point.
The existing attributes (both JSP and Thymeleaf) override the global setup.