deneb: add default_thai_company frappe app to poyerp

Package git.b4l.co.th/newedge/default_thai_company as a frappix app
    (pkgs/frappix/default-thai-company.nix) and expose it through a new
    frappixAppsOverlay that extends the pkgs.frappix scope. Install it on
    the poyerp.newedge.house site on deneb.

machines/deneb/configuration.nix

@@ -25,6 +25,7 @@ in
     inputs.self.overlays.frappixLibsOverlay
     inputs.self.overlays.frappixPythonOverlay
     inputs.self.overlays.frappixToolsOverlay
+    inputs.self.overlays.frappixAppsOverlay
   ];
 
   fonts.packages = [ pkgs.tlwg ];
@@ -59,6 +60,7 @@ in
       pkgs.frappix.hrms
       pkgs.frappix.crm
       pkgs.frappix.posprinter
+      pkgs.frappix.default_thai_company
     ];
     sites = {
       "${sitename}" = {
@@ -69,6 +71,7 @@ in
           "hrms"
           "crm"
           "posprinter"
+          "default_thai_company"
         ];
       };
     };