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-yasnippet.el

@@ -1,11 +1,12 @@
 ;; -*- coding: utf-8; lexical-binding: t; -*-
 
 (require 'init-package)
-(add-pkg-in-pkg-dir "yasnippet")
-(add-pkg-in-pkg-dir "yasnippet-snippets")
-(add-pkg-in-pkg-dir "auto-yasnippet")
 
-(require 'lazy-load)
+(creature/pkg-active 'yasnippet)
+(creature/pkg-active 'yasnippet-snippets)
+(creature/pkg-active 'auto-yasnippet)
+(creature/pkg-active 'lazy-load)
+
 (require 'yasnippet)
 (require 'yasnippet-snippets)