title: How to globally ignore errors with sentry v5 to reduce noise
body: <p>With the deprecated client Raven you could ignore troublesome errors : </p>
  
  <pre><code>Raven.config('your-dsn', {
      ignoreErrors: [
          'Can\'t execute code from freed script',
          /SecurityError\: DOM Exception 18$/
      ]
  }).install();
  </code></pre>
  
  <p>The only way I found with the new client is with the <code>before-send</code> hook :
  <a href="https://docs.sentry.io/error-reporting/configuration/filtering/?platform=browser#before-send" rel="noreferrer">https://docs.sentry.io/error-reporting/configuration/filtering/?platform=browser#before-send</a></p>
  
  <pre><code>import * as Sentry from '@sentry/browser';
  
  init({
    beforeSend(event, hint) {
      const { message } = hint.originalException;
      if (message &amp;&amp; message.match(/database unavailable/i)) {
        return null;
      }
      return event;
    }
  });
  </code></pre>
  
  <p>I searched all over the docs but didn't find a global way to ignore errors. </p>