Extensions: Add global CFG support

CFG is bundled as an extension which is more flexible in terms of
storing settings and consolidating code.

Global CFG is currently supported and the old power user setting
is auto-migrated.

Signed-off-by: kingbri <bdashore3@proton.me>

public/scripts/extensions/cfg/util.js

@@ -0,0 +1,9 @@
+import { extension_settings } from "../../extensions.js"
+
+// TODO: Update to use per-chat and per-character CFG
+export function getCfg() {
+    return { 
+        guidanceScale: extension_settings.cfg.global.guidance_scale,
+        negativePrompt: extension_settings.cfg.global.negative_prompt
+    }
+}