[Coupon] No cumulative coupon

Add the possibility to mark a coupon can’t be used with another coupon.

Example:

• CODE5 for 5% OFF
• CODE10 for 10€ off over 50€
  => Don’t be able to use CODE5 + CODE10 on the same order

Hey @Kad Darem , this can be set here - https://creator.tebex.io/coupons/settings