constistent classmethod and staticmethod usage

General idea is to use classmethod for every constructor and
statismethod otherwise.
Also use self and cls whenever it's possible to call static and class
methods

src/ahriman/core/status/client.py

@@ -19,7 +19,7 @@
 #
 from __future__ import annotations
 
-from typing import List, Optional, Tuple
+from typing import List, Optional, Tuple, Type
 
 from ahriman.core.configuration import Configuration
 from ahriman.models.build_status import BuildStatus, BuildStatusEnum
@@ -31,6 +31,20 @@ class Client:
     base build status reporter client
     """
 
+    @classmethod
+    def load(cls: Type[Client], configuration: Configuration) -> Client:
+        """
+        load client from settings
+        :param configuration: configuration instance
+        :return: client according to current settings
+        """
+        host = configuration.get("web", "host", fallback=None)
+        port = configuration.getint("web", "port", fallback=None)
+        if host is not None and port is not None:
+            from ahriman.core.status.web_client import WebClient
+            return WebClient(host, port)
+        return cls()
+
     def add(self, package: Package, status: BuildStatusEnum) -> None:
         """
         add new package with status
@@ -109,18 +123,3 @@ class Client:
         :param package: current package properties
         """
         return self.add(package, BuildStatusEnum.Unknown)
-
-    @staticmethod
-    def load(configuration: Configuration) -> Client:
-        """
-        load client from settings
-        :param configuration: configuration instance
-        :return: client according to current settings
-        """
-        host = configuration.get("web", "host", fallback=None)
-        port = configuration.getint("web", "port", fallback=None)
-        if host is None or port is None:
-            return Client()
-
-        from ahriman.core.status.web_client import WebClient
-        return WebClient(host, port)