Add nix-output-monitor to default packages

m/common/base/env.nix

@@ -5,6 +5,7 @@
     vim wget git htop tmux pciutils tcpdump ripgrep nix-index nixos-option
     nix-diff ipmitool freeipmi ethtool lm_sensors cmake gnumake file tree
     ncdu perf ldns pv
+    nix-output-monitor
     # From jungle overlay
     osumb nixgen
   ];