[Internal]: Add bulk alert suppression documentation

[vitaliidm]

Description

Feature is planned for 8.19/9.1.0

Resources

PR: elastic/kibana#223090
Issue: https://github.com/elastic/security-team/issues/9190

Which documentation set does this change impact?

Elastic On-Prem and Cloud (all)

Feature differences

Alert suppression is not available for Basic license
But available for Serverless Essentials tier

What release is this request related to?

9.1

Serverless release

n/a

Collaboration model

The documentation team

Point of contact.

Main contact: @vitaliidm

Stakeholders: @approksiu , @yctercero