Move Query Boost functionality from Advanced Search to Administration

The current's Query Boost found in the Advanced Search intent is to allow the change in relevance for fields *on the fly*.

This is truly and advanced functionality and is very useful for development. A normal user will not use that feature.

We could make it configurable if we want to display it or not (in the advanced area), but IMO a *configuration* query boost in administration that affects all the queries (and not the just the current query) would be more helpful.