refactor!: restructure Doom core

BREAKING CHANGE: This restructures the project in preparation for Doom
to be split into two repos. Users that have reconfigured Doom's CLI
stand a good chance of seeing breakage, especially if they've referred
to any core-* feature, e.g.

  (after! core-cli-ci ...)

To fix it, simply s/core-/doom-/, i.e.

  (after! doom-cli-ci ...)

What this commit specifically changes is:
- Renames all core features from core-* to doom-*
- Moves core/core-* -> lisp/doom-*
- Moves core/autoloads/* -> lisp/lib/*
- Moves core/templates -> templates/

Ref: #4273

bin/doom

@@ -62,7 +62,7 @@
 ;;   Put together, plus a strategically placed exit call, the shell will read
 ;;   one part of this file and ignore the rest, while the elisp interpreter will
 ;;   do the opposite.
-;; - I intentionally avoid loading site files, so core/core-cli.el can load them
+;; - I intentionally avoid loading site files, so lisp/doom-cli.el can load them
 ;;   by hand later. There, I can suppress and deal with unhelpful warnings (e.g.
 ;;   "package cl is deprecated"), "Loading X...DONE" spam, and any other
 ;;   disasterous side-effects.
@@ -107,7 +107,7 @@
 ;;
 ;;; Load Doom's CLI framework
 
-(require 'core-cli (expand-file-name "core/core-cli" user-emacs-directory))
+(require 'doom-cli (expand-file-name "lisp/doom-cli" user-emacs-directory))
 
 ;; Load $DOOMDIR/init.el, to read the user's `doom!' block, and so users can
 ;; customize things early, if they like.

bin/doomscript

@@ -40,7 +40,7 @@ tmpfile="$TMPDIR/doomscript.${__DOOMPID}"
 
 target="$1"
 shift
-$emacs --load "$EMACSDIR/core/core-cli" \
+$emacs --load "$EMACSDIR/lisp/doom-cli" \
        --load "$target" \
        -- "$@" || exit=$?
 # Execute exit-script, if requested (to simulate execve)