Add ID of scheduled maintenance to list group item

This allows us to use a static URL to a scheduled maintenance.

resources/views/partials/schedule.blade.php

@@ -5,7 +5,7 @@
         </div>
         <div class="list-group">
             @foreach($scheduled_maintenance as $schedule)
-            <div class="list-group-item">
+            <div class="list-group-item" id="scheduled-{{ $schedule->id }}">
                 <strong>{{ $schedule->name }}</strong> <small class="date"><abbr class="timeago" data-toggle="tooltip" data-placement="right" title="{{ $schedule->scheduled_at_formatted }}" data-timeago="{{ $schedule->scheduled_at_iso }}"></abbr></small>
                 <div class="markdown-body">
                     {!! $schedule->formatted_message !!}