Update our documentation regarding the configuration files

[carlspring]

Task Description

As a follow-up to #965, we need to update our documentation. We should:

• [x] Add a page called "The strongbox.yaml file" to the "User Guide" in the strongbox-docs.
• [x] Add a page called "The strongbox-authorization.yaml file" to the "User Guide" in the strongbox-docs.
• [x] Add a page called "The strongbox-cron-tasks.yaml file" to the "User Guide" in the strongbox-docs.
• [ ] Add a page called "The strongbox-security-users.yaml file" to the "User Guide" in the strongbox-docs.
• [ ] Update the Application Properties page.
• [x] Update the Routing Rules page.

Task Relationships

This task is a follow-up of #965.

[steve-todorov]

@carlspring what is expected to be updated in the Application Properties page?

[ggold7046]

@carlspring , @sbespalov , @fuss86

what is to be added into the files "The strongbox.yaml file", "The strongbox-authorization.yaml file" , "The strongbox-cron-tasks.yaml file", "The strongbox-security-users.yaml file" ?