- Define sitepolicy handler manager class, base class and the core handler
- Allow to set a plugin as sitepolicyhandler that implements the sitepolicy API
- Modify web services to return information from the 3rd party handler instead of core if needed
This was done for indicators, targets and time splitting methods so that we
can get the string identifier and component in order to display a help_icon.
The functions were also made abstract, removing the default implementation.
Indicators, targets and time splitting methods should define this function.
