CIP ? - Set minPoolCost to 0

I would prefer the minimum fee be reduced to 30 Ada because:

  • this doesn’t change the shape of the overall reward function
  • it revalues min fee to a similar USD amount compared with Shelley staking inception

See @Colin_Edwards post: Minimum Pool Fees (with a brief mention of K changes)

Given how difficult it is to model the effects of such changes, it might be safer to reduce min fee to 30 Ada.