Add a new authorization manager component that take care of external context

Using the directly the AuhorizationManager to check access is not appropriate since it does not take into account contextual aspect, like the dropPermission feature, or the upcoming signed script feature.

Using the XWikiCachingRightService from component is not pratical since it depends on old core and this is not a component.

So we need a new component, independent of old core that take into account the context to provide authorization.