[Feature] New payment mode by percentage

[Ampsicora]

Description

Would be cool allow people to send a percentage of forged lisk during a period of time to a specific address.

This payment is like the "donation" payment but with percentage value. Instead of send a specific amount of LSK (not calculated in the distribution) to an address, this payment allows to send a percentage of forged LSK, calculated from last payment timestamp, to an address.

Example

• Total forged in 1 week: 1200 LSK
• Percentage to send: 10%
• Total to send: 120 LSK