Extract user utility code into own module

This provides more room for expansion, and reduces the amount of
arbitrary code in the __init__.py file for the new package.

app/main/views/tour.py

@@ -9,7 +9,8 @@ from app.main.views.send import (
     get_placeholder_form_instance,
     get_recipient_and_placeholders_from_session,
 )
-from app.utils import get_template, user_has_permissions
+from app.utils import get_template
+from app.utils.user import user_has_permissions
 
 
 @main.route("/services/<uuid:service_id>/tour/<uuid:template_id>")