Simplify and decouple init files

The two doom-gc-* variables in init.el couples the rest of the config to
these two files. The bulk of GC/file-handler optimization was moved into
core.el and simplified (all that idle-timer voodoo was overkill).

Also adds (setq frame-inhibit-implied-reize t) to early-init, which
speeds up startup a fair bit in some edge cases with larger fonts.

squash! Simplify and decouple init files

modules/editor/snippets/autoload/snippets.el

@@ -19,7 +19,7 @@ you will be prompted to select one.
 If there are conflicting keys across the two camps, the built-in ones are
 ignored. This makes it easy to override built-in snippets with private ones."
   (when (eq this-command 'yas-expand)
-    (let* ((gc-cons-threshold doom-gc-cons-upper-limit)
+    (let* ((gc-cons-threshold most-positive-fixnum)
            (choices (cl-remove-duplicates choices :test #'+snippets--remove-p)))
       (if (cdr choices)
           (cl-loop for fn in (cdr (memq '+snippets-prompt-private yas-prompt-functions))