Access to other machines can be easily added into the "hosts" attribute without the need to replicate the configuration.
To accomodate the raccoon knights workstation, some of the configuration pulled by m/common/main.nix has to be removed. To solve it, the xeon specific parts are placed into m/common/xeon.nix and only the common configuration is at m/common/base.nix.
Reviewed-by: Rodrigo Arias Mallo <rodrigo.arias@bsc.es>
