Fix #1858, #1689: don't kill temp agenda buffers (yet)

Some commands expect temporary org agenda buffers (opened by org-agenda)
to remain open, so instead of proactively killing them we remap
org-agenda-quit and org-agenda-Quit to org-agenda-exit, which does that
for us at a more appropriate time: when closing the agenda.

modules/lang/org/config.el

@@ -464,7 +464,7 @@ eldoc string."
       "Prevent temporarily-opened agenda buffers from being associated with the
 current workspace (and clean them up)."
       (when (and org-agenda-new-buffers (bound-and-true-p persp-mode))
-        (let ((persp-autokill-buffer-on-remove t))
+        (let (persp-autokill-buffer-on-remove)
           (persp-remove-buffer org-agenda-new-buffers
                                (get-current-persp)
                                nil)))))
@@ -603,7 +603,11 @@ between the two."
     :keymap (make-sparse-keymap))
   (add-hook 'org-agenda-mode-hook #'org-agenda-localleader-mode)
 
-  (map! :map org-agenda-localleader-mode-map
+  (map! :map org-agenda-mode-map
+        ;; Always clean up after itself
+        [remap org-agenda-quit] #'org-agenda-exit
+        [remap org-agenda-Quit] #'org-agenda-exit
+        :map org-agenda-localleader-mode-map
         :localleader
         "d" #'org-agenda-deadline
         "q" #'org-agenda-set-tags