[listal] add 'image' & 'people' extractors (#1589 #8921)

* listal extractor
* add listal to init
* fix flake8 & formatting & extractor names/subcategories

* remove 're' import
* remove 'datetime' import
* update & simplify extractors
* update supportedsites
* add tests

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Co-authored-by: Mike Fährmann <mike_faehrmann@web.de>

scripts/supportedsites.py

@@ -240,6 +240,7 @@ SUBCATEGORY_MAP = {
     "issue"  : "Comic Issues",
     "manga"  : "Manga",
     "media"  : "Media Files",
+    "people" : "People",
     "popular": "Popular Images",
     "recent" : "Recent Images",
     "saved"  : "Saved Posts",