Add possibility to edit groovy macro with auto completion

This is to add the possibility to edit groovy macro with the full XWiki context. So by example typing services.query. will automatically suggested the method of the QueryManagerScriptService.

By adding something like @BaseScript ScriptContext mainScript at the top of the script we can say to the IDE to import the context from an other page and then declare the full context in this one.

Ideally we should have a same tools for velocity but currently I didn't find any IDE with auto-completion for velocity so a feature like this might be useless for velocity.