Setup MediaWiki to use ElasticSearch

[renoirb]

Wikimedia foundation pointed out that using ElasticSearch as search backend improves the wiki’s search performance and quality of the results.

Since we already have an ElasticSearch cluster, we could use it for that too.

Compare search result view WITH ElasticSearch and WITHOUT?

This is a screenshot of a search results from the same wiki entries, on the same day, with the same query "reg", but using distinct engines configured within MediaWiki.

The left side shows how ElasticSearch displays results while the right side shows using the default configuration.

Legend

• A; The title of the document has the search term highlighted
• B; If the result is found inside a particular section, the search result entry shows where
• C; Contents displayed shows only content and example code and hides internal MediaWiki syntax as we see in D.

[renoirb]

Dropping the ball, we won’t use. Refer to #177