core-lib: add auto-minor-mode, revise def-project-mode!

- Adds the auto-minor-mode package to replace our in-house
  implementation.
- Merges associate! into the def-project-mode! macro because associate!
  on its own is less useful than auto-minor-mode-alist,
  auto-minor-mode-magic-alist or hooks.
- Changes the semantics of :modes and :add-hooks properties of
  def-project-mode!. Its arguments are evaluated as is; lists will need
  to be quoted.

squash! core-lib: remove associate! macro

modules/lang/csharp/config.el

@@ -62,5 +62,5 @@
   (add-to-list 'auto-mode-alist '("\\.shader$" . shader-mode))
 
   (def-project-mode! +csharp-unity-mode
-    :modes (csharp-mode shader-mode)
+    :modes '(csharp-mode shader-mode)
     :files (and "Assets" "Library/MonoManager.asset" "Library/ScriptMapper")))