Switch Repository to non-enterprise

The enterprise repository requires a bought key, hence the usage of Proxmox in a homelab usually lead to the usage of the non-production repository.

1. Comment out everything with "#" in /etc/apt/sources.list/pve-enterprise.list

2. create new file in /etc/apt/sources.list/pve-no-enterprise.list

3. insert:

   deb http://download.proxmox.com/debian/pve buster pve-no-subscription

4. replace "buster" with name of debian version corresponding to Proxmox version.

Sources

https://pve.proxmox.com/wiki/Package_Repositories