Add version history view for timer functions

- Implement `/history/<function_id>` route in timer routes to fetch and display function versions
- Create new Mithril `DiffView` component for comparing script versions
- Add new history template for timer functions with version comparison
- Include version diff functionality using AceDiff library
- Update header and edit templates to include history URL for timer functions

templates/dashboard/timer_functions/edit.html

@@ -11,7 +11,8 @@ show_client=False,
 show_history=True,
 edit_url=url_for('timer.edit', function_id=function_id),
 cancel_url=url_for('timer.overview'),
-logs_url=url_for('timer.logs', function_id=function_id)) }}
+logs_url=url_for('timer.logs', function_id=function_id),
+history_url=url_for('timer.history', function_id=function_id)) }}
 
 
 <div id="app" class="p-1">