Adds one entry point for both JSON and MP APIs

Removes endpoints folder and moves versions to the root
JSON API folder

lib/API/JSON/v1/NewsletterTemplates.php

@@ -0,0 +1,59 @@
+<?php
+namespace MailPoet\API\JSON\v1;
+use MailPoet\API\JSON\Endpoint as APIEndpoint;
+use MailPoet\API\JSON\Error as APIError;
+
+use MailPoet\Models\NewsletterTemplate;
+
+if(!defined('ABSPATH')) exit;
+
+class NewsletterTemplates extends APIEndpoint {
+  function get($data = array()) {
+    $id = (isset($data['id']) ? (int)$data['id'] : false);
+    $template = NewsletterTemplate::findOne($id);
+    if($template === false) {
+      return $this->errorResponse(array(
+        APIError::NOT_FOUND => __('This template does not exist.', 'mailpoet')
+      ));
+    } else {
+      return $this->successResponse(
+        $template->asArray()
+      );
+    }
+  }
+
+  function getAll() {
+    $collection = NewsletterTemplate::findMany();
+    $templates = array_map(function($item) {
+      return $item->asArray();
+    }, $collection);
+
+    return $this->successResponse($templates);
+  }
+
+  function save($data = array()) {
+    $template = NewsletterTemplate::createOrUpdate($data);
+    $errors = $template->getErrors();
+
+    if(!empty($errors)) {
+      return $this->errorResponse($errors);
+    } else {
+      return $this->successResponse(
+        NewsletterTemplate::findOne($template->id)->asArray()
+      );
+    }
+  }
+
+  function delete($data = array()) {
+    $id = (isset($data['id']) ? (int)$data['id'] : false);
+    $template = NewsletterTemplate::findOne($id);
+    if($template === false) {
+      return $this->errorResponse(array(
+        APIError::NOT_FOUND => __('This template does not exist.', 'mailpoet')
+      ));
+    } else {
+      $template->delete();
+      return $this->successResponse(null, array('count' => 1));
+    }
+  }
+}