Major refactor & optimization of how modules load their packages

Now that we are loading package autoloads files (as part of the
generated doom-package-autoload-file when running make autoloads), many
:commands properties are redundant. In fact, many def-package! blocks
are redundant.

In some cases, we can do without a config.el file entirely, and can move
into the autoloads file or rely entirely on package autoloads.

Also, many settings have been moved in their module's autoloads files,
which makes them available ASAP; their use no longer depends on module
load order.

This gained me a modest ~10% boost in startup speed.

modules/lang/scala/config.el

@@ -1,26 +1,24 @@
 ;;; lang/scala/config.el -*- lexical-binding: t; -*-
 
-(def-package! scala-mode
-  :mode "\\.s\\(?:cala\\|bt\\)$"
-  :config (setq scala-indent:align-parameters t))
+(after! scala-mode
+  (setq scala-indent:align-parameters t)
+  (add-to-list 'dtrt-indent-hook-mapping-list '(scala-mode c/c++/java scala-indent:step)))
 
 
-(def-package! sbt-mode :after scala-mode)
-
-
-(def-package! ensime
-  :commands (ensime ensime-scala-mode-hook)
-  :hook (scala-mode . ensime-mode)
-  :config
-  (set! :company-backend 'scala-mode '(ensime-company company-yasnippet))
-
+(after! ensime
   (setq ensime-startup-snapshot-notification nil
         ensime-startup-notification nil
         ensime-eldoc-hints 'all
         ;; let DOOM handle company setup
         ensime-completion-style nil)
 
+  (set! :company-backend 'scala-mode '(ensime-company company-yasnippet))
+
   ;; Fix void-variable imenu-auto-rescan error caused by `ensime--setup-imenu'
   ;; trying to make imenu variables buffer local before imenu is loaded.
   (require 'imenu))
 
+
+(def-package! sbt-mode
+  :after scala-mode
+  :config (set! :repl 'scala-mode #'run-scala))