Docstring update (#58)

* migrate docstrings from reST to google format

* add raises note

Also change behaviour of the `from_option` method to fallback to
disabled instead of raising exception on unknown option

* fix part of warnings for sphinx

* make identation a bit more readable

* review fixes

* add verbose description for properties to make them parsed by sphinx extenstion

* add demo sphinx generator

tests/ahriman/application/handlers/test_handler_status.py

@@ -12,8 +12,12 @@ from ahriman.models.package import Package
 def _default_args(args: argparse.Namespace) -> argparse.Namespace:
     """
     default arguments for these test cases
-    :param args: command line arguments fixture
-    :return: generated arguments for these test cases
+
+    Args:
+        args(argparse.Namespace): command line arguments fixture
+
+    Returns:
+        argparse.Namespace: generated arguments for these test cases
     """
     args.ahriman = True
     args.exit_code = False