Improve documentation of managed resources, particularly user federations

[etluchs]

Problem Statement

From the documentation it is not clear, in which cases a certain resource will be deleted, or deleted and recreated by kcc.
It would be helpful if the documentation stated that:

• information about which resources were created by keycloak are stored as realm-attributes in the kc database
• kcc will by default delete and recreate a resource which was initially created by kcc
  • that behaviour can be disabled by the import.managed.* family of properties (i.e. setting them to no-delete)
• all of this applies to user-federations (LDAP, AD) and, in that case, results in users created by that federation being deleted (along with, for example, their offline tokens)

Proposed Solution

Enhance the documentation. I would be willing to create a PR for this.

Environment

• Keycloak Version: [e.g. 10.0.1]
• keycloak-config-cli Version: [e.g. 1.4.0]
• Java Version: [e.g. 11]

Additional information

No response

Acceptance Criteria

No response