Issue #3502055 - Add new filter

Related to #3502055

src/Plugin/FapiValidationFilter/LtrimFilter.php

+<?php
+
+namespace Drupal\fapi_validation\Plugin\FapiValidationFilter;
+
+use Drupal\fapi_validation\FapiValidationFiltersInterface;
+
+/**
+ * Fapi Validation Plugin for Ltrim filter.
+ *
+ * @FapiValidationFilter(
+ *   id = "ltrim"
+ * )
+ */
+class LtrimFilter implements FapiValidationFiltersInterface {
+
+  /**
+   * {@inheritdoc}
+   */
+  public function filter($value) {
+    return ltrim($value);
+  }
+
+}