Add basic FeaturesController

[MAILPOET-2008]

lib/Features/FeaturesController.php

@@ -0,0 +1,22 @@
+<?php
+
+namespace MailPoet\Features;
+
+class FeaturesController {
+
+  // Define features below in the following form:
+  //   const FEATURE_NAME_OF_FEATURE = 'name-of-feature';
+
+  // Define feature defaults in the array below in the following form:
+  //   self::FEATURE_NAME_OF_FEATURE => true,
+  public static $defaults = [
+  ];
+
+  /** @return bool */
+  function isSupported($feature) {
+    if (!array_key_exists($feature, self::$defaults)) {
+      throw new \RuntimeException("Unknown feature '$feature'");
+    }
+    return self::$defaults[$feature];
+  }
+}