[Nix] Adds MCP config.

system/hosts/mcp/zfs.nix

@@ -0,0 +1,9 @@
+{ config, pkgs, ... }:
+
+{
+  boot.supportedFilesystems = [ "zfs" ];
+  boot.zfs.forceImportRoot = false;
+  # Set up the pool to be imported on boot.
+  # Note that mountpoints are managed by ZFS on this system.
+  boot.zfs.extraPools = [ "tank" ];
+}