Add new selectsource template

mymodule/templates/selectsource.tpl.php

+<?php
+$this->data['header'] = $this->t('{multiauth:multiauth:select_source_header}');
+$this->includeAtTemplateBase('includes/header.php');
+?>
+
+<h2><?php echo $this->t('{multiauth:multiauth:select_source_header}'); ?></h2>
+
+<p><?php echo $this->t('{multiauth:multiauth:select_source_text}'); ?></p>
+
+<form action="/idp/module.php/multiauth/selectsource.php" method="get">
+    <input type="hidden" name="AuthState" value="<?php echo htmlspecialchars($this->data['authstate']); ?>" />
+    <ul>
+<?php
+foreach ($this->data['sources'] as $source) {
+    echo '<li class="'.htmlspecialchars($source['css_class']).' authsource">';
+    if ($source['source'] === $this->data['preferred']) {
+        $autofocus = ' autofocus="autofocus"';
+    } else {
+        $autofocus = '';
+    }
+    $name = 'src-'.base64_encode($source['source']);
+    echo '<input type="submit" name="'.htmlspecialchars($name).'"'.$autofocus.' '.
+        'id="button-'.htmlspecialchars($source['source']).'" '.
+        'value="'.htmlspecialchars($source['text']).'" />';
+    echo '</li>';
+}
+?>
+    </ul>
+</form>
+<?php $this->includeAtTemplateBase('includes/footer.php');