Parallel sync. Project issue

[Davidson-Souza]

One major feature of utreexo is allowing parallel sync efficiently. Parallel sync means that we can validate multiple blocks at the same time. This allows better usage of available resources, if compared to the usual linear syncing.

• Partial chainstate: We could just use the normal chainstate, but locking would take much of the CPU time anyways. To avoid that, we'll use a smaller, application-specific chainstate, called PartialChain
  • Move some validation code out of chainstate, so we can reduce repetition: https://github.com/Davidson-Souza/Floresta/pull/62
  • Implement partial chain states with tests: https://github.com/Davidson-Souza/Floresta/pull/63
  • Allow creating multiple partial chain states from a chainstate: create partial chainstates from a full chainstate #127
• Use partial chainstates in the node
• Simplify the IBD node to only use the partial chainstate
• Do Parallel IBD

Open Questions:

• Multiple nodes with one chain each, or only one node with multiple chains?