fix: remove missing PaymentMode and Taxes model references from setup script

[towfeeqkhan]

Bug

Running npm run setup fails due to missing models:

Cannot find module '../models/appModels/PaymentMode'
Cannot find module '../models/appModels/Taxes'

These models are referenced in src/setup/setup.js but do not exist in:

backend/src/models/appModels/

This prevents contributors from completing the initial project setup locally.

Fix

Removed invalid imports and related insert operations for:

• PaymentMode
• Taxes

These models are not present in backend/src/models/appModels/, so removing the references restores setup functionality without affecting runtime logic.

The setup script now completes successfully and creates:

• Admin user
• Default settings

Steps to reproduce

1. Clone the repository
2. Navigate to the backend folder
3. Run npm install
4. Run npm run setup

Before fix:

Setup fails with MODULE_NOT_FOUND error for PaymentMode and Taxes.

After fix:

Setup completes successfully without errors.

Screenshots

Before fix

After fix

Fixes #1434

Additional note

The setup controller (src/controllers/coreControllers/setup.js) also references these models and may require a similar update. I can submit a follow-up PR if needed.