chore(themes): Simplify theme initialization and setup

I've been using doom-themes' doom-vibrant for long enough now that I'm
certain I won't be moving away from it anytime soon. So let's simplify
and strip away all other theme setup stuff.

modules/editor/siren-doom-modeline.el

@@ -0,0 +1,25 @@
+;;; siren-doom-modeline.el --- jimeh's Emacs Siren: doom-modeline theme.
+
+;;; Commentary:
+
+;; Setup for doom-modeline theme.
+
+;;; Code:
+
+(use-package doom-modeline
+  :hook (after-init . doom-modeline-mode)
+
+  :custom
+  (doom-modeline-bar-width 3)
+  (doom-modeline-buffer-encoding nil)
+  (doom-modeline-buffer-file-name-style 'truncate-with-project)
+  (doom-modeline-buffer-modification-icon t)
+  (doom-modeline-buffer-state-icon t)
+  (doom-modeline-checker-simple-format t)
+  (doom-modeline-enable-word-count t)
+  (doom-modeline-height 25)
+  (doom-modeline-minor-modes t)
+  (doom-modeline-vcs-max-length 24))
+
+(provide 'siren-doom-modeline)
+;;; siren-doom-modeline.el ends here