logstash: Updates for udp2log filtering

* Add Bug58676
* Add CirrusSearch-failed
* Add CirrusSearch-slow
* Remove CirrusSearch
* Clean up apache2 logs
** Strip leading whitespace from message
** Discard "last message repeated" lines
** Extract message severity from message
* Fix scholarships parsing
** Tag for indexing by elasticsearch
** Parse the timestamp provided in the json data

Change-Id: I6d3b6305aeea3a5590595ea44dadac8bb5357fb6