Light node

[kpp]

In contrast with full-nodes, it's nice to have light nodes that can restore state from DA only.

A cycle for light node will be (given we have a starting DA block number):

• read block
• if BatchProof is found
  • check method id and proving system
  • if no elf found for method id - download it
• verify BatchProof
• apply StateDiff to the previous state to get the new state

It will require us to store a metadata for BatchProof to include method_id and the id of the proving system (e.g. either risc0 or sp1).

Also we will need to provide risc0 and sp1 method binaries (elfs) as a build artifact when we publish a new release.

Another option will be to embed a build system into light node to recompile all releases in order to get methods without relying on our artifacts from github, however it would solve a different issue. Instead of verifying & applying state diff, it would also verify method id, which is another issue at all.

[kpp]

This is described in #1354