Use overlay

Signed-off-by: Nikolaos Karaolidis <nick@karaolidis.com>

hosts/elara/default.nix

@@ -1,5 +1,12 @@
 { config, inputs, ... }:
 {
+  nixpkgs.overlays = [
+    inputs.lib.overlays.default
+    inputs.self.overlays.default
+    inputs.nur.overlays.default
+    inputs.sas.overlays.default
+  ];
+
   imports = [
     ./options.nix
 
@@ -7,6 +14,8 @@
     ./format.nix
     ./hardware
 
+    inputs.sas.nixosModules.default
+
     ../common/configs/system
 
     ../common/configs/system/bluetooth
@@ -47,11 +56,10 @@
     ../common/configs/system/users
     ../common/configs/system/zsh
 
+    ./configs/globalprotect
     ./configs/pki
     ./configs/ssh
 
-    "${inputs.sas}/hosts/elara/configs/globalprotect"
-
     ./users/nikara
   ];