Add support for Elasticsearch authentication.

Author: GUI

templates/etc/rsyslog.conf.mustache

@@ -168,6 +168,12 @@ local0.info action(
   type="omelasticsearch"
   server="{{elasticsearch._first_server.host}}"
   serverport="{{elasticsearch._first_server.port}}"
+  {{#elasticsearch._first_server.user}}
+  uid="{{elasticsearch._first_server.user}}"
+  {{/elasticsearch._first_server.user}}
+  {{#elasticsearch._first_server.password}}
+  pwd="{{elasticsearch._first_server.password}}"
+  {{/elasticsearch._first_server.password}}
   searchIndex="elasticsearch-index"
   dynSearchIndex="on"
   searchType="log"