Add Google Drive authorization processing and error handling templates

- Implemented `google_drive_callback.html` for processing Google Drive authorization, including UI for success and error states.
- Added JavaScript functionality for exchanging authorization codes, saving settings, and handling folder selection.
- Created `google_drive_callback_error.html` to display error messages during the authorization process.

app/views/__init__.py

@@ -10,6 +10,7 @@ from app.views.files import router as files_router
 from app.views.status import router as status_router
 from app.views.dropbox import router as dropbox_router
 from app.views.onedrive import router as onedrive_router
+from app.views.google_drive import router as google_drive_router
 
 # Create a combined router
 router = APIRouter()
@@ -20,3 +21,4 @@ router.include_router(files_router)
 router.include_router(status_router)
 router.include_router(dropbox_router)
 router.include_router(onedrive_router)
+router.include_router(google_drive_router)