Add warning when adding macros without a license

[oanalavinia]

Since macros are registered independently of an existing license, these can be added to a page even if the license does not yet exists. The macros are not fully functional in this case, because Licensing removes the view right on the macro page.

A message should be displayed to users. This should be done at the code level of each macro.

[oanalavinia]

Example https://github.com/xwikisas/application-diagram/blob/master/application-diagram-ui/src/main/resources/Diagram/DiagramMacro.xml#L327