[General+Flake] convert "default" module directory to subflake

Also move flatpak config from packages to desktop

flake.nix

@@ -0,0 +1,60 @@
+{
+  inputs = {
+    nixpkgs-22_11.url = "github:NixOS/nixpkgs/nixos-22.11";
+    nixpkgs.url = "github:NixOS/nixpkgs/nixos-23.05";
+    nixpkgs-unstable.url = "github:NixOS/nixpkgs/nixpkgs-unstable";
+    nixpkgs-master.url = "github:NixOS/nixpkgs/master";
+
+    nur.url = "github:nix-community/NUR";
+
+    fps.url = "github:wamserma/flake-programs-sqlite";
+    fps.inputs.nixpkgs.follows = "nixpkgs";
+
+    pre-commit-hooks.url = "github:cachix/pre-commit-hooks.nix";
+    pre-commit-hooks.inputs.nixpkgs.follows = "nixpkgs";
+
+    flake-utils-plus.url = "github:gytis-ivaskevicius/flake-utils-plus";
+
+    sddm-unstable = {
+      url = "github:sddm/sddm/develop";
+      flake = false;
+    };
+  };
+
+  outputs =
+    inputs@{ self
+    #, flake-utils-plus
+    , nixpkgs
+    , nur
+    , nixpkgs-unstable
+    , fps
+    , ...
+    }: let
+      lib = nixpkgs.lib;
+      myLib = import ./lib {
+        inherit lib;
+      };
+      mkPkgs = pkgs: { system ? system
+                     , config
+                     , overlays ? [ ]
+                     , ...
+                     }: import pkgs { inherit system config overlays; };
+    in {
+      inherit self inputs myLib;
+
+      overlays.default = final: prev:
+        self.overlay
+          final
+          (nur.overlay final prev)
+        ;
+
+      overlay = (final: prev: {});
+
+      nixosModules = rec {
+        aviallon = import ./default.nix;
+        default = aviallon;
+      };
+
+      specialArgs = inputs // { inherit myLib; };
+    };
+}