[Feature](securitygroups): Add information that security groups work only for VMs

[edda]

Description

Security groups work only for virtual machines not for baremetal servers. This information is stated in the customer documentation but can be easily missed.

Problem Statement

It's easy to miss that security groups only work for virtual machines.

Proposed Solution

Add an info message to the security group plugin with the following text:

"Note: Security groups apply to virtual servers only. For baremetal server security options, please refer to our documentation."

Additional Context

SCoCH ticket