Automatically detect fields depending on search results

* if you search, it would be nice if we show a dialog containing the fields that gave a results and select the ones you'd like to add

No files, tests, or entry points are named. Start by tracing how searches are handled and where result fields are displayed, then inspect the Elasticsearch integration and existing field-selection UI. Done means a search opens a dialog listing fields found in its results and lets the user select fields to add.

Written by the indexing model from the issue text.