[danbooru] extend and improve URL regex

- add support for danbooru mirrors:
  - hijiribe.donmai.us
  - sonohara.donmai.us
  - todo: actually use these domains instead of redirecting everything
          to danbooru itself
- improve handling of query string parameters

gallery_dl/extractor/danbooru.py

@@ -19,16 +19,21 @@ class DanbooruExtractor(booru.JSONBooruExtractor):
 
 class DanbooruTagExtractor(DanbooruExtractor, booru.BooruTagExtractor):
     """Extractor for images from danbooru based on search-tags"""
-    pattern = [r"(?:https?://)?danbooru\.donmai\.us/posts"
-               r"\?(?:utf8=%E2%9C%93&)?tags=([^&]+)"]
-    test = [("https://danbooru.donmai.us/posts?tags=bonocho", {
-        "content": "b196fb9f1668109d7774a0a82efea3ffdda07746",
-    })]
+    pattern = [r"(?:https?://)?(?:danbooru|hijiribe|sonohara)\.donmai\.us"
+               r"/posts\?(?:[^&#]*&)*tags=([^&#]+)"]
+    test = [
+        ("https://danbooru.donmai.us/posts?tags=bonocho", {
+            "content": "b196fb9f1668109d7774a0a82efea3ffdda07746",
+        }),
+        ("https://hijiribe.donmai.us/posts?tags=bonocho", None),
+        ("https://sonohara.donmai.us/posts?tags=bonocho", None),
+    ]
 
 
 class DanbooruPoolExtractor(DanbooruExtractor, booru.BooruPoolExtractor):
     """Extractor for image-pools from danbooru"""
-    pattern = [r"(?:https?://)?danbooru\.donmai\.us/pools/(\d+)"]
+    pattern = [r"(?:https?://)?(?:danbooru|hijiribe|sonohara)\.donmai\.us"
+               r"/pools/(\d+)"]
     test = [("https://danbooru.donmai.us/pools/7659", {
         "content": "b16bab12bea5f7ea9e0a836bf8045f280e113d99",
     })]
@@ -36,7 +41,8 @@ class DanbooruPoolExtractor(DanbooruExtractor, booru.BooruPoolExtractor):
 
 class DanbooruPostExtractor(DanbooruExtractor, booru.BooruPostExtractor):
     """Extractor for single images from danbooru"""
-    pattern = [r"(?:https?://)?danbooru\.donmai\.us/posts/(\d+)"]
+    pattern = [r"(?:https?://)?(?:danbooru|hijiribe|sonohara)\.donmai\.us"
+               r"/posts/(\d+)"]
     test = [("https://danbooru.donmai.us/posts/294929", {
         "content": "5e255713cbf0a8e0801dc423563c34d896bb9229",
     })]
@@ -44,8 +50,8 @@ class DanbooruPostExtractor(DanbooruExtractor, booru.BooruPostExtractor):
 
 class DanbooruPopularExtractor(DanbooruExtractor, booru.BooruPopularExtractor):
     """Extractor for popular images from danbooru"""
-    pattern = [r"(?:https?://)?danbooru\.donmai\.us/"
-               r"explore/posts/popular()(?:\?([^#]*))?"]
+    pattern = [r"(?:https?://)?(?:danbooru|hijiribe|sonohara)\.donmai\.us"
+               r"/explore/posts/popular()(?:\?([^#]*))?"]
     test = [
         ("https://danbooru.donmai.us/explore/posts/popular", None),
         (("https://danbooru.donmai.us/explore/posts/popular"