change Chapter and MangaExtractor classes

- unify and simplify constructors
- rename get_metadata and get_images to just metadata() and images()
- rename self.url to chapter_url and manga_url

gallery_dl/extractor/mangapanda.py

@@ -17,15 +17,6 @@ class MangapandaBase():
     root = "https://www.mangapanda.com"
 
 
-class MangapandaMangaExtractor(MangapandaBase, MangareaderMangaExtractor):
-    """Extractor for manga from mangapanda.com"""
-    pattern = r"(?:https?://)?((?:www\.)?mangapanda\.com/[^/?&#]+)/?$"
-    test = ("https://www.mangapanda.com/mushishi", {
-        "url": "357f965732371cac1990fee8b480f62e29141a42",
-        "keyword": "031b3ea085921c552de017ecbb9b906e462229c9",
-    })
-
-
 class MangapandaChapterExtractor(MangapandaBase, MangareaderChapterExtractor):
     """Extractor for manga-chapters from mangapanda.com"""
     pattern = r"(?:https?://)?(?:www\.)?mangapanda\.com((/[^/?&#]+)/(\d+))"
@@ -33,3 +24,12 @@ class MangapandaChapterExtractor(MangapandaBase, MangareaderChapterExtractor):
         "url": "1f633f776e950531ba9b1e81965316458e785261",
         "keyword": "32b5e84017c2bf5f122b339ecf40899e41f18cc9",
     })
+
+
+class MangapandaMangaExtractor(MangapandaBase, MangareaderMangaExtractor):
+    """Extractor for manga from mangapanda.com"""
+    pattern = r"(?:https?://)?(?:www\.)?mangapanda\.com(/[^/?&#]+)/?$"
+    test = ("https://www.mangapanda.com/mushishi", {
+        "url": "357f965732371cac1990fee8b480f62e29141a42",
+        "keyword": "031b3ea085921c552de017ecbb9b906e462229c9",
+    })