Event log switching to all needs to add this option to elasticsearch if being used

[Robert Lyon]

Currently, by default the elasticsearch options are for things like views, user, artefacts etc.

But once you set the Site config to do logging and turn on 'Event log reporting' it means that elasticsearch will be used for some of the reports.

However, when turning on this option we don't yet add 'event_log' to the plugin_search_elasticsearch_types value, nor do we re-index the site to add this data mapping in

So ideally when the site config is saved and if elasticsearch is running we do theses updates as part of the saving process