Web UI Session Timer customization needs to be documented

[kalroy]

User Story

Web UI session timer is set by default as "3m" if SAML is not configured as connector.
In case SAML is configured as connector the session timer is "24h"

As an admin, I should be able to change the default configuration so that when user is idle the UI should log out by itself.

We need to document these steps properly and following the documentation guideline.

Acceptance Criteria

• This only talks about the documentation perspective
• No user interface is available to set the changes
• For a deployed instance, the admin has to patch the config. That would cause a small amount of time needed for Dex to restart when UI will be unreachable.
• In scenarios with multiple concurrent Automate instances, the patch has to run on every instance

Definition of Done

• Documentation should be following the public web doc structure
• The PR should be reviewed and approved by at least two approvals for docs team
• Netlify preview should be reviewed before merging
• All pipelines should be green

Demo Script / Repro Steps

Aha! Link: https://chef.aha.io/epics/SH-E-516

[kalroy]

We will add the documentation part once we fix the UI idle session timeout being worked as #5381

[kalroy]

@dishanktiwari2501 We are planning to get #5381 merged in the current sprint.