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

lisp/cli/run.el

@@ -0,0 +1,103 @@
+;;; lisp/cli/run.el --- launching Emacs in a sandbox -*- lexical-binding: t; -*-
+;;; Commentary:
+;;; Code:
+
+;;
+;;; Variables
+
+;; None yet!
+
+
+;;
+;;; Commands
+
+(defcli! run
+    (;; TODO Implement sandbox functionality post-3.0
+     ;; (daemon?     ("--daemon"))
+     ;; (window-type ("--gui" "--tty"))
+     ;; (version     ("--with-emacs" version))
+     ;; (doomversion ("--with-doom" version))
+     ;; (profile     ("--profile" name))
+     (repl?  ("--repl") "Launch an elisp REPL")
+     ;; &multiple
+     ;; (calls  ("-f" "--funcall" fn))
+     ;; (loads  ("-l" "--load" file))
+     ;; (evals  (     "--eval" form))
+     &context context
+     &input input
+     &rest args)
+  "Launch Doom Emacs or an Emacs sandbox
+
+Opens from bin/doom's parent directory.
+
+Keep in mind there is some overhead opening Doom this way. For the best
+performance, it is best to run Doom out of ~/.config/emacs or ~/.emacs.d."
+  :benchmark nil
+  ;; TODO Implement sandbox functionality post-3.0
+  ;; (when version
+  ;;   (unless (executable-find "nix-shell")
+  ;;     (user-error "--emacs option is not supported without nix"))
+  ;;   ...)
+  (if repl?
+      (if input
+          ;; Evaluate piped-in text directly, if given.
+          (eval (read input) t)
+        (doom-run-repl context))
+    ;; TODO Does this work on Windows?
+    (let* ((tempdir      (doom-path (temporary-file-directory) "doom.run"))
+           (tempemacsdir (doom-path tempdir ".emacs.d")))
+      (delete-directory tempdir t)
+      (make-directory tempemacsdir t)
+      (with-temp-file (doom-path tempemacsdir "early-init.el")
+        (prin1 `(progn
+                  (setenv "HOME" ,(getenv "HOME"))
+                  (setq user-emacs-directory ,doom-emacs-dir)
+                  (load-file ,(doom-path doom-emacs-dir "early-init.el")))
+               (current-buffer)))
+      (exit! (format "HOME=%S %s %s"
+                     tempdir
+                     invocation-name
+                     (combine-and-quote-strings args))))))
+
+
+;;
+;;; Helpers
+
+(defun doom-run-repl (context)
+  "Launch a rudimentary Elisp REPL."
+  ;; I wrote this for fun; not with any serious intention of adding a
+  ;; fully-fledged REPL to the Doom CLI. Still, I occasionally need to check
+  ;; something, and once this has nix integration and can sandbox Emacs versions
+  ;; separately, it may be useful for quick tests and demos.
+  (let (form)
+    (while (setq form (read-from-minibuffer "(elisp) $ "))
+      (when (member form '(":quit" ":q"))
+        (print! "\nGoodbye!")
+        (exit! 0))
+      (let (debug-on-error)
+        (condition-case e
+            (print! "%S" (eval (read form) t))
+          (error
+           (let* ((n 0)
+                  (frame (backtrace-frame n))
+                  (frame-list nil)
+                  (in-program-stack t))
+             (while frame
+               (when in-program-stack
+                 (push (cdr frame) frame-list))
+               ;; (when (eq (elt frame 1) 'doom-run-repl)
+               ;;   (setq in-program-stack t))
+               (when (eq (elt frame 1) 'doom-run-repl)
+                 (setq in-program-stack nil))
+               (setq n (1+ n)
+                     frame (backtrace-frame n)))
+             (let* ((depth doom-cli-backtrace-depth)
+                    (print-escape-newlines t))
+               (print! (error "There was an unexpected error"))
+               (print-group!
+                (print! "%s %s" (bold "Message:") (error-message-string e))
+                (print! "%s %S" (bold "Details:") (cdr e))))))))
+      (terpri))))
+
+(provide 'doom-cli-run)
+;;; run.el ends here