[rawkuma] add support (#4571)

* Add rawkuma extractor

* Fix flake8 warnings

* Remove fstring

* Fix regex call

* update domain to rawkuma.net

* fix 'manga' extractor

* fix 'chapter' extractor

* add tests

* update docs/supportedsites

---------

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

test/results/rawkuma.py

@@ -0,0 +1,65 @@
+# -*- coding: utf-8 -*-
+
+# This program is free software; you can redistribute it and/or modify
+# it under the terms of the GNU General Public License version 2 as
+# published by the Free Software Foundation.
+
+from gallery_dl.extractor import rawkuma
+
+
+__tests__ = (
+{
+    "#url"     : "https://rawkuma.net/hitman-chapter-127/",
+    "#class"   : rawkuma.RawkumaChapterExtractor,
+    "#pattern" : r"https://cdn.kumacdn.club/wp-content/uploads/images/h/hitman/chapter-127/.+\.jpg$",
+    "#count"   : 18,
+
+    "chapter"      : 127,
+    "chapter_id"   : 313750,
+    "chapter_minor": "",
+    "count"        : 18,
+    "date"         : "dt:2021-07-01 07:07:27",
+    "extension"    : "jpg",
+    "filename"     : str,
+    "lang"         : "ja",
+    "language"     : "Japanese",
+    "manga"        : "Hitman",
+    "manga_id"     : 47920,
+    "page"         : range(1, 18),
+    "thumbnail"    : "https://rawkuma.net/wp-content/uploads/2020/10/Hitman-10.jpg",
+    "title"        : "End",
+},
+
+{
+    "#url"     : "https://rawkuma.net/saikyou-inyoushi-no-isekai-tenseiki-chapter-8-1/",
+    "#class"   : rawkuma.RawkumaChapterExtractor,
+    "#pattern" : r"https://cdn.kumacdn.club/wp-content/uploads/images/s/saikyou-inyoushi-no-isekai-tenseiki/chapter-8-1/.+\.jpg$",
+
+    "chapter"      : 8,
+    "chapter_id"   : 85076,
+    "chapter_minor": ".1",
+    "count"        : 11,
+    "date"         : "dt:2023-11-21 06:27:19",
+    "extension"    : "jpg",
+    "filename"     : str,
+    "lang"         : "ja",
+    "language"     : "Japanese",
+    "manga"        : "Saikyou Inyoushi no Isekai Tenseiki",
+    "manga_id"     : 20781,
+    "page"         : range(1, 11),
+    "thumbnail"    : "https://rawkuma.net/wp-content/uploads/2020/06/Saikyou-Inyoushi-no-Isekai-Tenseiki-cover.jpg",
+    "title"        : "",
+},
+
+{
+    "#url"     : "https://rawkuma.net/manga/hitman/",
+    "#class"   : rawkuma.RawkumaMangaExtractor,
+    "#pattern" : rawkuma.RawkumaChapterExtractor.pattern,
+
+    "chapter"      : range(1, 127),
+    "chapter-minor": {"", ".5"},
+    "manga"        : "Hitman",
+    "title"        : {"", "End"},
+},
+
+)