syncrule/index: add missing index file

fixes #12031

application/views/scripts/syncrule/index.phtml

@@ -0,0 +1,58 @@
+<div class="controls">
+<?= $this->tabs ?>
+<h1><?= $this->escape($this->title) ?></h1>
+</div>
+
+<div class="content">
+<?php if (! $this->run): ?>
+<p class="warning">
+<?= $this->translate('This Sync Rule has never been run before.') ?>
+</p>
+<?php endif ?>
+<?php if ($rule->sync_state === 'unknown'): ?>
+<p><?= $this->translate(
+    "It's currently unknown whether we are in sync with this rule."
+    . ' You should either check for changes or trigger a new Sync Run.'
+) ?></p>
+<?php elseif ($rule->sync_state === 'in-sync'): ?>
+<p><?= sprintf(
+    $this->translate(
+        'This Sync Rule was last found to by in Sync at %s.'
+    ),
+    $rule->last_attempt
+) /*
+TODO: check whether...
+      - there have been imports since then, differing from former ones
+      - there have been activities since then
+*/ ?></p>
+<?php elseif ($rule->sync_state === 'pending-changes'): ?>
+<p class="warning"><?= $this->translate(
+    'There are pending changes for this Sync Rule. You should trigger a new'
+    . ' Sync Run.'
+) ?></p>
+<?php elseif ($rule->sync_state === 'failing'): ?>
+<p class="error"><?= sprintf(
+    $this->translate(
+        'This Sync Rule failed when last checked at %s: %s'
+    ),
+    $rule->last_attempt,
+    $rule->last_error_message
+) /*
+TODO: check whether...
+      - there have been imports since then, differing from former ones
+      - there have been activities since then
+*/ ?></p>
+<?php endif ?>
+<?php if ($this->run): ?>
+ <h3><?= $this->translate('Last sync run details') ?></h3>
+ <?= $this->render('syncrule/syncRunDetails.phtml') ?><br />
+<?php if ($run->rule_name !== $rule->rule_name): ?>
+<?= $this->escape(sprintf(
+    $this->translate("It has been renamed since then, it's former name was %s"),
+    $run->rule_name
+)) ?>
+
+<pre><?= $this->escape( print_r($this->run->getProperties(), 1)); ?></pre>
+
+<?php endif ?>
+<?php endif ?>