refactor: introduce doom-context

Introduces a system to announce what execution contexts are active, so I
can react appropriately, emit more helpful logs/warnings in the case of
issues, and throw more meaningful errors.

* bin/doom: load module CLIs in the 'modules' context.
* lisp/cli/doctor.el: load package files in 'packages' context.
* lisp/doom-cli.el:
  - (doom-before-init-hook, doom-after-init-hook): trigger hooks at the
    correct time. This may increase startup load time, as the benchmark
    now times more of the startup process.
  - (doom-cli-execute, doom-cli-context-execute,
    doom-cli-context-restore, doom-cli-context-parse,
    doom-cli--output-benchmark-h, doom-cli-call, doom-cli--restart,
    doom-cli-load, run!): remove redundant context prefix in debug logs,
    it's now redundant with doom-context, which doom-log now prefixes
    them with.
* lisp/doom-lib.el (doom-log): prefix doom-context to doom-log output,
  unless it starts with :.
* lisp/doom-packages.el (package!, doom-packages--read): throw error if
  not used in a packages.el file or in the context of our package
  manager.
* lisp/doom-profiles.el (doom-profile--generate-init-vars,
  doom-profile--generate-load-modules): use modules doom-context instead
  of doom-init-time to detect startup.
* lisp/doom-start.el (doom-load-packages-incrementally-h): move function
  closer to end of doom-after-init-hook.
* lisp/doom.el:
  - (doom-before-init-hook, doom--set-initial-values-h,
    doom--begin-init-h): rename doom--set-initial-values-h to
    doom--begin-init-h and ensure it runs as late in
    doom-before-init-hook as possible, as that is the point where Doom's
    "initialization" formally begins.
  - (doom-after-init-hook): don't trigger at the end of command-line-1
    in non-interactive sessions. This will be triggered manually in
    doom-cli.el's run!.
* lisp/lib/config.el (doom/reload, doom/reload-autoloads,
  doom/reload-env): use 'reload' context for reload commands.
* modules/lang/emacs-lisp/autoload.el (+emacs-lisp-eval): use 'eval'
  context.
* modules/lang/org/config.el: remove doom-reloading-p; check for
  'reload' doom context instead.

modules/lang/emacs-lisp/autoload.el

@@ -14,7 +14,8 @@ to a pop up buffer."
       (unwind-protect
           (condition-case-unless-debug e
               (let ((doom--current-module (ignore-errors (doom-module-from-path buffer-file-name))))
-                (eval-region beg end buffer load-read-function)
+                (doom-context-with 'eval
+                  (eval-region beg end buffer load-read-function))
                 (with-current-buffer buffer
                   (let ((pp-max-width nil))
                     (require 'pp)