Majorly re-organize modules

- Split large modules into smaller parts (e.g. siren-text-manipulation)
- Organize modules into high level groups:
  - completion
  - core
  - editor
  - languages
  - linting
  - misc
  - navigation
  - projects
  - spelling
  - text-editing
  - version-control
  - windows
  - workspaces

modules/languages/siren-lua.el

@@ -0,0 +1,22 @@
+;;; siren-lua.el --- jimeh's Emacs Siren: lua-mode configuration.
+
+;;; Commentary:
+
+;; Basic configuration for lua-mode.
+
+;;; Code:
+
+(use-package lua-mode
+  :hook
+  (lua-mode . siren-lua-mode-setup)
+
+  :init
+  (defun siren-lua-mode-setup ()
+    (setq lua-indent-level 2
+          whitespace-action '(auto-cleanup))
+
+    (highlight-indentation-current-column-mode)
+    (subword-mode +1)))
+
+(provide 'siren-lua)
+;;; siren-lua.el ends here