[points-to-credits-fixes] Fix some points-to-credits (Privátny)

// Without this function 99 Kč -> 98.99989898989 (99.001123) // With this function 99 Kč -> 100 Kč // Expected behaviour 99 Kč -> 99 Kč

• payment sometimes not being paired and deposit transaction fails to process
• emails saying “Points” instead of “Credits” + weird numbers (0.4 points)
• sometimes wrong amount of credits is being deposited (99 => 100)
• ecommerce tracking codes not working (ecomail + GA)
• purchase table discounts being calculated in weird way (200 Kč + 10% = 280 Kč)