Provide Logstash Grok filters to cbcollect_info logs

Provide Logstash Grok (https://www.elastic.co/guide/en/logstash/current/plugins-filters-grok.html#plugins-filters-grok) filters which can be applied optionally either during or after log collection for  Couchbase Server logs collected with cbcollect_info. These filters are meant to make logs easier to interpret (structured) and query-able. The logs can also be added to a user's ELK stack (https://www.elastic.co/what-is/elk-stack).