adding a lucene command to remove the idx :data tree in order to allow d...

Just adding a new command to remove the :data node of the idx_path provided for cases when it is not possible to remove it anymore via any other mean and also to be independent of the store implementation, for example with mongodb it used to be done using oak mongo js script, as that is not possible with TarMK or other store, it make sense to have a solution that is generic.

Please review it and add it if you like that idea.