Epic #65815: Improve Indexed search indexer
indexed_search does not properly index XLSX and PPTX files
Working on a client's install, it turns out indexed_search is not capable of properly indexing XLSX and PPTX files.
- Problem for XLSX: the wrong "unzipped" file is indexed, that file contains some kind of metadata which are basically only pointers (integers). The content extracted is plain wrong and useless
- Problem for PPTX: only the content of Slide 1 is extracted, it misses content from all other slides