Add The Apache Solr Term Proximity module for better relevancy in Solr search results

I propose that we add the small but useful Apache Solr Term Proximity module for better relevancy in Solr searches. The module's project page describes what it odes and why it is useful. This module was written in response to people's complaints that searches for multiple words (i.e. "green beans") weren't returning relevant results. The module reportedly fixed those issues.