Initially we planned to run jobs in those nodes by sharing the same nix
store from hut. However, these nodes are now used to build packages
which are not available in hut. Users also ssh to the nodes, which
doesn't mount the hut store, so it doesn't make much sense to keep
mounting it.
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: Aleix Roca Nonell <aleix.rocanonell@bsc.es>
