feat: usos sign-in, private calendar feed and timetable archive

.pre-commit-config.yaml

@@ -0,0 +1,13 @@
+repos:
+  - repo: local
+    hooks:
+      - id: fmt
+        name: fmt
+        entry: make fmt
+        language: system
+        pass_filenames: false
+      - id: check
+        name: check
+        entry: make check
+        language: system
+        pass_filenames: false