Provide fixed amount discounts in invoicing

• Business users will now be able to provide fixed-amount discounts in invoices

• This is applicable for both one-time as well as recurring invoices

• This comes in addition to the percentage-based discounts, so users will now have an option to give 10% off or $100 off, for example, depending on the use cases.

• Any tax calculation on individual items will be done after deducting the discount amounts, so the customer will not be paying any taxes on the discounts offered.