Use the new DPLA marmotta-jetty

This unifies us on a single servlet container for Solr and Marmotta. It also pins us to a snapshot of Marmotta 3.3.0, which current LDP work depends on. We're expecting an official 3.3.0 release imminently.

When building for the first time with this update, you may need to remove any lingering Marmotta files by doing `rm -rf /tmp/marmotta`.