Add logs view for timer functions

- Create new database table `timer_function_invocations` to track function executions
- Implement `/logs/<function_id>` route in timer routes to fetch and display invocation logs
- Add new logs template for timer functions with detailed invocation information
- Update header templates to include logs URL for timer functions

templates/dashboard/http_functions/history.html

@@ -9,7 +9,8 @@ show_logs=True,
 show_client=True,
 show_history=True,
 edit_url=url_for('http_function_editor', function_id=function_id),
-cancel_url=url_for('dashboard_http_functions')) }}
+cancel_url=url_for('dashboard_http_functions'),
+logs_url=url_for('get_http_function_logs', function_id=function_id)) }}
 
 <!-- Timeline -->
 <div>