- 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
