WIP: Probabilistic Intra-Infrastructure Payments

WIP:

• There are many ways to do this, Livepeer probably has the most up to date production system which has been demonstrated to work on-chain
  • https://github.com/livepeer/wiki/blob/master/spec/streamflow/pm.md
  • https://medium.com/livepeer-blog/streamflow-probabilistic-micropayments-f3a647672462#:~:text=The%20Livepeer%20network%20connects%20broadcasters,orchestrators%20for%20transcoding%20the%20segments.
• This paper for the CacheCash blockchain CDN system seems to be highly relevant also: https://ssl.engineering.nyu.edu/papers/almashaqbeh_microcash_fc20.pdf
• We should implement this as a standalone pallet that other Substrate chains can use, this also makes it feasible to apply for W3F funding also.
• We should implement this in a way that it can be used across various purposes in the system, e.g. for Gateways and storage and content directory. Ideally, all without requiring any on-chain integrations between those systems, but rather just using this as a general utility pallet. In fact, we already have a p2p payment channel solution used in the Gateway system, but this propobablistic approach should allow pooling capital in a way which is far more efficient.

Start by reading the linked Livepeer Streamflow specification and the CacheCash paper to compare probabilistic payment designs. Define the scope of a standalone pallet usable by Gateways, storage, and the content directory, with pooled capital and no required on-chain integrations between those systems; the issue does not name repository files or tests.