runtime: Add mkvs::OverlayTree and use it in the dispatcher

[kostko]

No description provided.

[codecov]

Codecov Report

Merging #3499 (2661a29) into master (8e4c4e8) will increase coverage by 0.24%.
The diff coverage is 93.75%.

@@            Coverage Diff             @@
##           master    #3499      +/-   ##
==========================================
+ Coverage   66.25%   66.49%   +0.24%     
==========================================
  Files         373      373              
  Lines       33954    33956       +2     
==========================================
+ Hits        22495    22579      +84     
+ Misses       8176     8100      -76     
+ Partials     3283     3277       -6     

Impacted Files	Coverage Δ
go/storage/mkvs/syncer/proof.go	83.01% <90.00%> (+0.84%)	⬆️
go/storage/mkvs/iterator.go	80.29% <100.00%> (-0.29%)	⬇️
go/storage/mkvs/lookup.go	72.04% <100.00%> (-0.59%)	⬇️
go/storage/mkvs/overlay.go	70.37% <100.00%> (+0.37%)	⬆️
go/consensus/tendermint/api/api.go	74.66% <0.00%> (-10.67%)	⬇️
go/consensus/tendermint/abci/state/state.go	54.54% <0.00%> (-9.10%)	⬇️
...consensus/tendermint/apps/registry/transactions.go	57.45% <0.00%> (-2.21%)	⬇️
go/storage/mkvs/insert.go	90.41% <0.00%> (-1.37%)	⬇️
go/consensus/tendermint/abci/state.go	69.38% <0.00%> (-1.37%)	⬇️
.../consensus/tendermint/apps/registry/state/state.go	54.57% <0.00%> (-1.27%)	⬇️
... and 30 more

---

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 8e4c4e8...2661a29. Read the comment docs.