Add a Score implementation based on Optimally Reliable & Cheap Payment Flows on the Lightning Network by Rene Pickhardt and Stefan Richter [1].
Given the uncertainty of channel liquidity balances, probability distributions are defined based on knowledge learned from successful and unsuccessful attempts. Then the negative log of the success probability is used to determine the cost of routing a specific HTLC amount through a channel.
Knowledge about channel liquidity balances takes the form of upper and lower bounds on the possible liquidity. Certainty of the bounds is decreased over time using a decay function.
Resolves #1170.
Resolves #1172.