Global Saved searches usable with Roles

## What?
Hello,

Searching around gave me these "similar" requests:
https://community.graylog.org/t/saved-searchs-can-we-have-a-global-and-user-search-list/217
https://github.com/Graylog2/graylog2-server/issues/6810
https://github.com/Graylog2/graylog2-server/issues/6596

Aside from the great questions above, was wondering if possible to have the searches under system/authentication/roles?

## Why?
So an admin can provide "default" searches to all users.

## Your Environment
Using graylog behing nginx in subdirectory.

* Graylog Version: 3.2.2
* Elasticsearch Version: 6.8.6
* MongoDB Version: 4.0.16
* Operating System: CentOS 7.7.1908
* Kernel: 3.10.0-1062.12.1.el7.x86_64

Apologize if a duplicate!
Hope it's clear.
Thank you for the great support!!

-Dave