This commit refactors the Proxmox repository management tasks by adding necessary comments for better understanding. It also ensures that `apt update` is triggered whenever there are changes to the repository configuration.
This refactoring includes updating the README, changing the role name to focus on Proxmox VE, enhancing compatibility matrix, and refactoring default values for role variables. Handlers are updated to manage apt cache, restart pveproxy, and reload systemd. Role metadata is also updated for better Proxmox VE provisioning.
