Enable partial burning of fee pool balance in the distribution strategy

[jeisses]

A recent proposal was accepted to burn a part of the feepool before reward distribution:
https://dashboard.effect.ai/proposals/17

This feature needs to be researched and implemented in the feepool smart contract.

By voting yes on this proposal, you endorse the team establishing a toggleable mechanism in the smart contract that can burn 50% of network fees prior to distribution when enabled (or publishing a proposal on such a thing if this proposal is insufficiently technical). Initially, it will be disabled and another proposal will be required to enable network fee burning.