Support for Maximum Caps on Percentage-Based Tax Rules

Problem Statement:

• Currently, tax rules in Hospitable support either a flat percentage or a fixed amount. However, some regions require a percentage-based tax that is capped at a maximum amount per person/night.
• Without this capability, users are forced to manually adjust charges to avoid overcharging or undercharging their guests.

Example: A user may need to collect a tourist tax of 5% of the nightly rate per guest, but with a maximum cap of €4.90.

Proposed Solution: Add an optional "Maximum Cap" field to percentage-based tax rules that limits the tax amount to a specific value.