Improvements for K-Fêt CMS.

K-Fêt - Wagtail
- Page content becomes a StreamField.
- GroupTeam snippet becomes a block for stream field.
- Navigation menu moved becomes a "flatmenu", preventing possible future conflicts.
- Page layout can be modified in wagtail admin.

K-Fêt
- Add shorthands for ukf account balance/article price.
- Cleaning stylesheets and templates.

kfet/utils.py

@@ -0,0 +1,10 @@
+import math
+
+from .config import kfet_config
+
+
+def to_ukf(balance, is_cof=False):
+    """Convert euro to UKF."""
+    subvention = kfet_config.subvention_cof
+    grant = (1 + subvention / 100) if is_cof else 1
+    return math.floor(balance * 10 * grant)