feat: Add Activity export

See #27
See #29
Resolves #24

export/views/activities.py

@@ -0,0 +1,9 @@
+from . import base
+from .. import serializers
+
+from activities import models
+
+
+class ActivityExportView(base.CsvExportView):
+    model = models.Activity
+    serializer_class = serializers.activities.ActivitySerializer