Refactored file structure to make more sense, made default.nixes less verbose

modules/sys/software/nixvim/default.nix

@@ -0,0 +1,12 @@
+{
+  config,
+  pkgs,
+  ...
+}: {
+	imports = [
+		./plugins
+		./options.nix
+		./keymaps.nix
+		./autocmd.nix
+	];
+}