[kemono][coomer][schalenetwork] rename modules & extractors

category changes:

- kemonoparty -> kemono
- coomerparty -> coomer
- koharu      -> schalenetwork

also wanted to rename '2chan' -> 'sturdychan',
but the site's main page is still titled '2chen'

docs/gallery-dl.conf

@@ -191,7 +191,7 @@
             "quality" : "original=true",
             "quality-videos": "quality=100"
         },
-        "coomerparty":
+        "coomer":
         {
             "username": "",
             "password": "",
@@ -376,7 +376,7 @@
             "sleep-request": "0.5-1.5",
             "videos": true
         },
-        "kemonoparty":
+        "kemono":
         {
             "username": "",
             "password": "",
@@ -399,16 +399,6 @@
             "covers": false,
             "format": "mp3"
         },
-        "koharu":
-        {
-            "username": "",
-            "password": "",
-            "sleep-request": "0.5-1.5",
-
-            "cbz"   : true,
-            "format": ["0", "1600", "1280", "980", "780"],
-            "tags"  : false
-        },
         "luscious":
         {
             "gif": false
@@ -571,6 +561,16 @@
             "embeds": false,
             "videos": true
         },
+        "schalenetwork":
+        {
+            "username": "",
+            "password": "",
+            "sleep-request": "0.5-1.5",
+
+            "cbz"   : true,
+            "format": ["0", "1600", "1280", "980", "780"],
+            "tags"  : false
+        },
         "scrolller":
         {
             "username": "",