Move pre/post query backend methods to events

Patch file with static plain diff of issue 3435998-post_query_event and 8.x-7.x branches. Contains the event definition and trigger. Also deprecates the postQuery method.

New one updated with the last fixings.

manuel.adan → changed the visibility of the branch 3435998-post_query_event to hidden.

Extended the issue to the pre query method as well.

I found that current implementation calls pre query method after building the request params, so query alterations have no effects. It was fixed.

Now the active issue branch is 3435998-pre_post_query_events

Updated static patch file.