Please configure and enable mod_deflate for onionoo.torproject.org on omeiense

Context: So far, the Jetty process running on port 8080 where Apache was forwarding requests was previously deflating responses using the following filter:

  <filter>
    <filter-name>GzipFilter</filter-name>
    <filter-class>org.eclipse.jetty.servlets.GzipFilter</filter-class>
    <init-param>
      <param-name>mimeTypes</param-name>
      <param-value>text/html,text/xml,text/plain,application/json</param-value>
    </init-param>
    <init-param>
      <param-name>excludedAgents</param-name>
      <param-value>gozilla,traviata</param-value>
    </init-param>
    <init-param>
      <param-name>minGzipSize</param-name>
      <param-value>2048</param-value>
    </init-param>
  </filter>

  <filter-mapping>
    <filter-name>GzipFilter</filter-name>
    <url-pattern>/*</url-pattern>
  </filter-mapping>

But I fear that this caused problems in combination with Apache's mod_cache module (see #18663 (moved) for details if you care a whole lot). I want to try moving all response post-processing to Apache, which would include compression and caching.

Can we build something similar as the Jetty filter above (not necessarily the exact same thing) using Apache's mod_deflate module?