use "creature/pkg-active" manage packages manually

- replace "add-pkg-in-pkg-dir" (recursive load-path scanning) with a
  central "creature/pkgs" registry that handles load path, autoloads,
  info dirs and dependencies
- adapt all init-*.el files to the new activation function
- add a top-level Makefile to byte-compile site-lisp packages
- remove unused "emacs-kv" and "emacs-db" submodules

lisp/init-gptel.el

@@ -1,6 +1,8 @@
 ;; -*- coding: utf-8; lexical-binding: t; -*-
 
-(add-pkg-in-pkg-dir "gptel")
+(require 'init-package)
+
+(creature/pkg-active 'gptel)
 
 (let ((gptel-autoload-file
        (file-name-concat creature/cache-dir "gptel-autoloads.el")))