💥 Replace package.el/quelpa with straight #374

There are a few kinks to iron out, but for the most part it's done. Doom
Emacs, powered by straight. Goodbye gnutls and elpa/quelpa issues.

This update doesn't come with rollback or lockfile support yet, but I
will eventually include one with Doom, and packages will be (by default,
anyway) updated in sync with Doom.

Relevant threads: #1577 #1566 #1473

README.md

@@ -34,7 +34,7 @@
 **Quick start**
 ```bash
 git clone https://github.com/hlissner/doom-emacs ~/.emacs.d
-~/.emacs.d/bin/doom quickstart
+~/.emacs.d/bin/doom install
 ```
 
 **Table of Contents**