feat(reth-bench): add file-based block loading for benchmarks (#19162)

[Charlie-Mack]

Resolves #19162 when complete

Summary

Adds file-based block loading to reth-bench, allowing benchmarks to replay blocks from pre-generated files instead of fetching from an RPC.

Changes

• Added block-storage command to generate block files from RPC
• Implemented BlockFileReader with configurable batch reading for memory efficiency
• Added --from-file flag to benchmark commands
• Refactored to use BlockSource enum for clean RPC/File separation
• Made auth provider optional (only required for actual benchmarking, not file generation)
• Added support for early optimism blocks (Engine API v1 not supported in Optimism)

Usage

# Generate block file
reth-bench block-storage --rpc-url  --from X --to Y --output ./blocks

# Run benchmark from file
reth-bench new-payload-fcu --from-file ./blocks/blocks.bin --jwt-secret