Allow to save transaction senders to disk

[peroket]

[peroket]

Co-authored with @pat-comity

[codecov[bot]]

Codecov Report

Merging #660 (e177e89) into master (30319b2) will increase coverage by 0.01%. The diff coverage is 90.90%.

@@            Coverage Diff             @@
##           master     #660      +/-   ##
==========================================
+ Coverage   82.89%   82.90%   +0.01%     
==========================================
  Files         177      177              
  Lines       15254    15275      +21     
==========================================
+ Hits        12645    12664      +19     
- Misses       2609     2611       +2     

Impacted Files	Coverage Δ
node/silkworm/db/access_layer.cpp	83.98% <90.90%> (+0.29%)	:arrow_up:
core/silkworm/state/in_memory_state.cpp	94.14% <0.00%> (-0.98%)	:arrow_down:
core/silkworm/consensus/base/engine.cpp	94.02% <0.00%> (+0.99%)	:arrow_up:

---

Continue to review full report at Codecov.

Legend - Click here to learn more Δ = absolute <relative> (impact), ø = not affected, ? = missing data Powered by Codecov. Last update 30319b2...e177e89. Read the comment docs.

[canepat]

The proposed changes seem not to fit well into the Silkworm codebase for the reasons already outlined in previous comments by @AndreaLanfranchi.

Generally speaking, usage of Silkworm as a library even without relying on the staged sync loop is absolutely possible and we're keen to support it, but in this specific case the write_senders function seems better suited for inclusion in the application code rather than in Silkworm itself.