Refactor Star Wars Journal module structure and styles

- Replaced `main.js` with `asc-starwars.js` and modularized journal sheet logic into `journalSheets.js`.
- Updated `module.json` to use ES modules and adjusted script/style references accordingly.
- Consolidated and enhanced CSS styles into `asc-starwars-journal.css` and added `asc-ffg-starwars.css`.
- Removed deprecated `starwars-journal.css` and outdated journal sheet registration logic.

src/module.json

@@ -6,6 +6,9 @@
     "minimum": "12",
     "verified": "12"
   },
-  "scripts": ["scripts/main.js"],
-  "styles": ["styles/starwars-journal.css"]
+  "esmodules": ["scripts/asc-starwars.js"],
+  "styles": [
+    "styles/asc-ffg-starwars.css",
+    "styles/asc-starwars-journal.css"
+  ]
 }