Goal: Update pre-installation documentation for connected and disconnected server installation for use with foremanctl

Existing documentation: Pre-installation documentation in the connected and disconnected installation guides:

• "Planning Satellite Server installation" chapter
• "Preparing environment for Satellite Server installation" chapter

Link to the connected guide: https://docs.redhat.com/en/documentation/red_hat_satellite/6.18/html-single/installing_satellite_server_in_a_connected_network_environment/index 

Link to the disconnected guide: https://docs.redhat.com/en/documentation/red_hat_satellite/6.18/html-single/installing_satellite_server_in_a_disconnected_network_environment/index 

Acceptance criteria: The above-mentioned chapters have been reviewed and updated for a containerized installation, and included in the corresponding version of the installation guides.