Validate & Redeem coupons

Number of APIs: 3

1. Coupon redemption POST {{api-url}}/caas-coupon/{{tenant}}/coupons/{{couponId}}/redemptions

2. Access Token validation&redeem POST {{api-url}}/oauth/token

3. Coupon validation POST {{api-url}}/caas-coupon/{{tenant}}/coupons/{{couponId}}/validation