💥 Replace core-popup with new feature/popup module

This is a breaking change! Update your :popup settings. Old ones will
throw errors!

Doom's new popup management system casts off its shackles (hur hur) and
replaces them with the monster that is `display-buffer-alist`, and
window parameters.

However, this is highly experimental! Expect edge cases.  Particularly
with org-mode and magit (or anything that does its own window
management).

Relevant to #261, #263, #325

modules/completion/ivy/config.el

@@ -84,7 +84,6 @@ immediately runs it on the current candidate (ending the ivy session)."
   (setq counsel-find-file-ignore-regexp "\\(?:^[#.]\\)\\|\\(?:[#~]$\\)\\|\\(?:^Icon?\\)")
 
   ;; Configure `counsel-rg', `counsel-ag' & `counsel-pt'
-  (set! :popup 'ivy-occur-grep-mode :size (+ 2 ivy-height) :regexp t :autokill t)
   (dolist (cmd '(counsel-ag counsel-rg counsel-pt))
     (ivy-add-actions
      cmd