New add application usecase, improved add_classification usecase and better defaults for owner settings. Thanks johltn

src/ifcopenshell-python/ifcopenshell/api/owner/add_application.py

@@ -0,0 +1,9 @@
+class Usecase:
+    def __init__(self, file, **settings):
+        self.file = file
+        self.settings = {"attributes": None}
+        for key, value in settings.items():
+            self.settings[key] = value
+
+    def execute(self):
+        return self.file.create_entity("IfcApplication", **self.settings["attributes"])