docs: Add HW requirements for the Regional controller role

In "Multi-region deployments" feature a new "Regional controller" role was introduced bur it is nowhere mentioned which HW requirements this role should satisfy. Could you please add the section which describes HW requirements for this role both for Bare metal or for the VM if applicable?

Start with the “Multi-region deployments” documentation and locate the existing description of the “Regional controller” role and hardware requirements for comparable roles. Determine the requirements for bare-metal and VM deployments where applicable, then add a dedicated section and verify that both deployment options are covered.

Written by the indexing model from the issue text.