remove @staticmethod decorators

There might have been a time when calling a static method was faster
than a regular method, but that is no longer the case. According to
micro-benchmarks, it is 70% slower in CPython 3.13 and it also makes
executing the code of a class definition slower.

gallery_dl/postprocessor/compare.py

@@ -62,12 +62,10 @@ class ComparePP(PostProcessor):
     def _compare(self, f1, f2):
         return self._compare_size(f1, f2) and self._compare_content(f1, f2)
 
-    @staticmethod
-    def _compare_size(f1, f2):
+    def _compare_size(self, f1, f2):
         return os.stat(f1).st_size == os.stat(f2).st_size
 
-    @staticmethod
-    def _compare_content(f1, f2):
+    def _compare_content(self, f1, f2):
         size = 16384
         with open(f1, "rb") as fp1, open(f2, "rb") as fp2:
             while True:

gallery_dl/postprocessor/metadata.py

@@ -268,8 +268,7 @@ class MetadataPP(PostProcessor):
         if not private:
             return util.filter_dict
 
-    @staticmethod
-    def _make_encoder(options, indent=None):
+    def _make_encoder(self, options, indent=None):
         return json.JSONEncoder(
             ensure_ascii=options.get("ascii", False),
             sort_keys=options.get("sort", False),

gallery_dl/postprocessor/ugoira.py

@@ -425,15 +425,13 @@ class UgoiraPP(PostProcessor):
 
         return (None, None)
 
-    @staticmethod
-    def _delay_gcd(frames):
+    def _delay_gcd(self, frames):
         result = frames[0]["delay"]
         for f in frames:
             result = gcd(result, f["delay"])
         return result
 
-    @staticmethod
-    def _delay_is_uniform(frames):
+    def _delay_is_uniform(self, frames):
         delay = frames[0]["delay"]
         for f in frames:
             if f["delay"] != delay: