roothash/api: rename Genesis.Blocks -> RuntimeStates

[matevz]

PR for #2426:

• replaces roothash.Genesis.Blocks with map storing api.RuntimeGenesis objects,
• adds RuntimeGenesis.Round and --runtime.genesis.round flag,
• on InitChain() generates runtime genesis block using RuntimeGenesis instead of block,
• replaces RuntimeGenesis.StorageReceipt with StorageReceipts i.e. one receipt per storage node,
• adds sanity checks for RuntimeGenesis including StorageSignatures verification of StateRoot and tests for it,
• adds RuntimeGenesis struct to rust,
• adds base64 serialization/deserialization of Bytes in rust.

[codecov]

Codecov Report

Merging #2462 into master will increase coverage by 0.18%.
The diff coverage is 62.9%.

@@            Coverage Diff             @@
##           master    #2462      +/-   ##
==========================================
+ Coverage   66.76%   66.94%   +0.18%     
==========================================
  Files         324      324              
  Lines       29887    29893       +6     
==========================================
+ Hits        19953    20013      +60     
+ Misses       7453     7388      -65     
- Partials     2481     2492      +11

Impacted Files	Coverage Δ
go/registry/api/api.go	42.09% <0%> (-0.16%)	⬇️
go/oasis-node/cmd/debug/storage/export.go	47.82% <100%> (+0.92%)	⬆️
go/consensus/tendermint/apps/roothash/genesis.go	100% <100%> (ø)	⬆️
go/oasis-node/cmd/registry/runtime/runtime.go	60.07% <100%> (+0.3%)	⬆️
go/consensus/tendermint/apps/roothash/roothash.go	69.44% <100%> (+0.76%)	⬆️
go/registry/tests/tester.go	87.71% <100%> (ø)	⬆️
go/registry/api/runtime.go	44.89% <33.33%> (-3.76%)	⬇️
go/roothash/api/api.go	80.95% <33.33%> (+19.84%)	⬆️
go/oasis-node/cmd/genesis/genesis.go	50% <8.33%> (+0.23%)	⬆️
go/common/namespace.go	62.5% <0%> (-12.5%)	⬇️
... and 16 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 b4d818b...a3940c4. Read the comment docs.

[kostko]

Signature contexts should not be moved.

[kostko]

Few minor nits, otherwise looks good now.