Get rid of debug.txt IDs list

Merge parser.py and mod_xmlfilter.py into one script.
The content of debug.txt could be moved into a in-memory list, then use the list as a source of IDs to get the output XML with only the required elements.
Note that the output XML should be 1 XML object (with 1 opening and 1 closing tag), currently they are several concatenated XML.