title: Wordpress REST API: Filter custom post type with multiple filters
body: <p>I've a custom post type "products" for which I created custom field with the <em>Advanced Custom Fields</em> (ACF) plugin.</p>
  
  <p>When I request <em>products</em> with <code>/wp-json/wp/v2/products</code> every product has acf attributes e.g.:</p>
  
  <pre><code>"acf": {
    "rating": 77
    "fun-factor": 10,
    "something": 65,
    …
  }
  </code></pre>
  
  <p>Now I filter my <code>products</code> by my attribute by <code>/wp-json/wp/v2/products?filter[meta_key]=rating&amp;filter[meta_value]=77</code> and would get my <em>product</em> above back as an result. So far so good.</p>
  
  <p>Now I've two things I want to accomplish:</p>
  
  <ul>
  <li>Show <em>products</em> with a <em>rating</em> range between 67-87, so <em>value - 10</em> and <em>value + 10</em></li>
  <li>Do the request with multiple filters</li>
  </ul>
  
  <p>Im happy for any input!</p>