Ability for user to delete one or more "last used query strings"

## What?

It should be possible for a user to delete one or more of their "last used query strings".

## Why?

1. A user might want to start fresh and reset their query string history.
2. A user might've accidentally searched for something they shouldn't have, or the query has some other issue, and they want to delete just the problematic history record.
3. This would be consistent with what users expect from browsers, etc.

Related to #17948 and #18067.

## Your Environment

* Graylog Version: `5.2.3`, but the feature will land in whatever is up next for the default branch (`6.0.0`?)