feat: adds a ListenerSubscriberInterface

Added to the ListenerProvider namespace. Accepts a
PrioritizedListenerAttachmentInterface argument, to which it will
subscribe listeners.

Author: weierophinney

TODO-PSR-14.md

@@ -46,9 +46,9 @@
       `getListenersForEventByPriority()` method of each, returning the
       aggregated listeners in priority order.
   - [x] Make `SharedEventManager` an extension of `PrioritizedIdentifierListenerProvider`
-  - [ ] Create `ListenerSubscriberInterface`
-    - [ ] `attach(PrioritizedListenerAttachmentInterface $provider, $priority = 1)`
-    - [ ] `detach(PrioritizedListenerAttachmentInterface $provider)`
+  - [x] Create `ListenerSubscriberInterface`
+    - [x] `attach(PrioritizedListenerAttachmentInterface $provider, $priority = 1)`
+    - [x] `detach(PrioritizedListenerAttachmentInterface $provider)`
   - [ ] Create `AbstractListenerSubscriber` and/or `ListenerSubscriberTrait`
     - [ ] define a default `detach()` implementation
   - [ ] Create `LazyListenerSubscriber` based on `LazyListenerAggregate`

src/ListenerProvider/ListenerSubscriberInterface.php

@@ -0,0 +1,22 @@
+<?php
+/**
+ * @see       https://github.com/zendframework/zend-eventmanager for the canonical source repository
+ * @copyright Copyright (c) 2019 Zend Technologies USA Inc. (https://www.zend.com)
+ * @license   https://github.com/zendframework/zend-eventmanager/blob/master/LICENSE.md New BSD License
+ */
+
+namespace Zend\EventManager\ListenerProvider;
+
+interface ListenerSubscriberInterface
+{
+    /**
+     * @param  int $priority Default priority at which to attach composed listeners.
+     * @return void
+     */
+    public function attach(PrioritizedListenerAttachmentInterface $provider, $priority = 1);
+
+    /**
+     * @return void
+     */
+    public function detach(PrioritizedListenerAttachmentInterface $provider);
+}