Stability/error-handling refactor (part 1)

This refactor is about improving how Emacs deals with errors.

A large net is now cast at startup to catch possible errors, produce
more helpful error messages, and localize the damage. Significantly
reducing the risk of later modules not loading (and leaving you
stranded in a half-broken Emacs session).

The DOOM core files are an exception. If something messes up in there,
it *should* choke.

+ use-package will now report missing packages or slow-loading/broken
  def-package! configurations.
+ Persp-mode no longer (inadvertantly) hides buffers that pop up at
  startup, like the *Warnings*, *Backtrace* or debugger buffers.
+ `make autoloads` (or doom/reload-autoloads) now produces a slightly
  more informative error message if an error occurs while building the
  autoloads file.
+ Error handling for package management is *slightly* better now; error
  messages now include the type of error; this needs work.

bin/doctor

@@ -153,7 +153,7 @@
              (gnutls-verify-error t))
          (dolist (url '("https://elpa.gnu.org/packages/archive-contents"
                         "https://melpa.org/packages/archive-contents"))
-           (condition-case ex
+           (condition-case-unless-debug ex
                (let (result)
                  (let ((inhibit-message t))
                    (url-retrieve url (lambda (status &rest _) (setq result status))))
@@ -169,7 +169,7 @@
                 (explain! (pp-to-string ex))))))
          (dolist (url '("https://self-signed.badssl.com"
                         "https://wrong.host.badssl.com/"))
-           (condition-case ex
+           (condition-case-unless-debug ex
                (let (result)
                  (let ((inhibit-message t))
                    (url-retrieve url (lambda (status &rest _) (setq result status))))