fix: derive devfee from config and calculate fee for miners

[owenashurst]

Just a little refactor to derive the DevFee from config instead of being hardcoded.

• Removed unnecessary line breaks
• Refactored out DevFee to be config driven
• Added fee method to calculate what reward the miner should get after the devFee

[warioishere]

hi, what is dev fee for? jst made an issue but the maintainer never answers questions. How does it work. I dont see any logic for it in the master branch

#113

[owenashurst]

hi, what is dev fee for? jst made an issue but the maintainer never answers questions. How does it work. I dont see any logic for it in the master branch

#113

If a miner was to find a block, and the dev fee is set to say, 1%, then the pool owner will take a 1% commission from the block reward.