Add a CLI tool to generate Golden validator storage-key sets during network bootstrap

[kkovaacs]

Validator startup requires Golden storage-key material:

• A shared setup-context.wire
• A shared public-key-set.wire
• A distinct secret-share.wire for each validator
• The corresponding 32-byte storage-key epoch

Currently, the only code that generates a complete key set (in the node repo) is the ignored storage_key::tests::write_insecure_golden_fixture test. That implementation is deterministic and hard-codes a two-of-three validator setup, making it unsuitable for bootstrapping a new network.

Add supported tool(s), preferably as a miden-validator subcommand, that generates and writes all the files that are required to bootstrap the network.

Steps to bootstrap should be added to the documentation as well.

@bobbinth, @huitseeker Please clarify how exactly the bootstrap procedure should be performed.

[bobbinth]

This probably could be a part of the validator binary - but I'm still trying to figure out what commands we'd need. My understanding currently:

• We'd need a command to generate the setup context. Can this be done by a single validator or does it require some collaboration?
• Each validator then would contribute their public key. I'm assuming someone would need to collect these keys manually.
• Then, we'd be able to derive the secrete share for each validator based on public key set and the setup context.

It feels like I'm missing something here. @huitseeker - could you correct/fill-in the gaps?

Also, would be good to update node's docs to include the procedure for setting up the validator set.

[huitseeker]

The abstract setup is laid out here: https://github.com/0xMiden/golden-dkg/blob/main/crates/golden-ehtdh1/examples/threshold_records.rs#L319-L399 — I'll take on the issue.