Add environment variables.

nodes/hosts/common/system/environment.nix

@@ -0,0 +1,18 @@
+{ pkgs, ... }: {
+
+  environment = {
+    # Optional, hint electron apps to use wayland:
+    sessionVariables = {
+      NIXOS_OZONE_WL = "1";
+      STEAM_EXTRA_COMPAT_TOOLS_PATHS = "/home/jay/.steam/root/compatibilitytools.d";
+    };
+
+    shellAliases = {
+      ls = "lsd -la";
+      ryujinx = "flatpak run io.github.ryubing.Ryujinx";
+    };
+
+    # Get plasma integration with browsers to work better.
+    etc."chromium/native-messaging-hosts/org.kde.plasma.browser_integration.json".source = "${pkgs.kdePackages.plasma-browser-integration}/etc/chromium/native-messaging-hosts/org.kde.plasma.browser_integration.json";
+  };
+}