Benchmark RISC-V zkVM

[georgwiese]

This should include:

• Set of Rust tests.
• Find complex Rust tests that fit in 1 chunk, so we don’t need continuations.
• https://github.com/powdr-labs/powdr-revme.
• R0 and SP1 benchmarks (sort of depends on Rust STD support).
• Collect data on witgen and proving time separately, generate nice looking data.

Perhaps this issue should be split into multiple.

[georgwiese]

@leonardoalt Should we close this issue? Seems to vague, and benchmarking is kind of an ongoing task. I just opened #2029 and #2030 for two concrete tasks.