title: Password file instead plain text password in kafka ssl setup
body: <p>If a system generates password and keys per host and copies (there are approx 50 hosts with differnt passwords) them to specified location on each host</p>
  <pre><code>i.e. on host host1
  
  /a/b/c/xyj_host1.p12
  /a/b/c/xyj_host1.p12.pwd 
  </code></pre>
  <p>In <em>server.properties</em> file of kafka <strong>I want to specify file location instead plain password</strong> for kafka (reason: I deploy on those 50+ servers using Ansible and its security hole if I have to specify password at the time of deployment)</p>
  <pre><code>ssl.truststore.location=/a/b/c/xyj_host1.p12
  # instead of passoword I want to specify the file which contains password
  ssl.truststore.password=/a/b/c/xyj_host1.p12.pwd  
  </code></pre>
  <p>How can I make above happen ?</p>