Modify runtime descriptors to support ADR 0004

[abukosek]

Closes #3450.

TODO:

• fix e2e tests.
• fix unit tests.
• remove SignedRuntime entirely.
• double-check that oasis-node debug fix-genesis command does the right thing.
• write a few changelog fragments.
• when 3511 is merged, fix the TODO in go/consensus/tendermint/apps/registry/transactions.go.
• update docs.
• add enable_runtime_governance_models consensus parameter & tests for it.
• add more tests.

In a separate PR:

• add update_runtime runtime message support & e2e tests.

[codecov]

Codecov Report

Merging #3548 (ca84d78) into master (25b63aa) will increase coverage by 0.08%.
The diff coverage is 64.56%.

@@            Coverage Diff             @@
##           master    #3548      +/-   ##
==========================================
+ Coverage   67.23%   67.31%   +0.08%     
==========================================
  Files         390      390              
  Lines       36540    36667     +127     
==========================================
+ Hits        24567    24683     +116     
- Misses       8524     8529       +5     
- Partials     3449     3455       +6     

Impacted Files	Coverage Δ
go/oasis-node/cmd/ias/auth_genesis.go	47.82% <0.00%> (+1.67%)	⬆️
go/staking/api/slashing.go	77.77% <0.00%> (-9.73%)	⬇️
go/consensus/tendermint/apps/registry/genesis.go	41.74% <36.36%> (+1.18%)	⬆️
go/oasis-node/cmd/registry/runtime/runtime.go	59.13% <41.02%> (+1.44%)	⬆️
go/registry/api/api.go	49.20% <45.23%> (-0.62%)	⬇️
go/registry/api/sanity_check.go	67.17% <50.00%> (+0.68%)	⬆️
...consensus/tendermint/apps/registry/transactions.go	58.69% <59.45%> (+2.07%)	⬆️
go/registry/api/runtime.go	45.85% <61.29%> (+3.20%)	⬆️
.../consensus/tendermint/apps/registry/state/state.go	59.07% <65.00%> (+3.87%)	⬆️
...nsus/tendermint/apps/supplementarysanity/checks.go	41.71% <66.66%> (ø)
... and 35 more

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[kostko]

Don't forget to update the documentation and add tests for the new features (whitelist changes, minimum pool size, submitting register runtime txes for consensus/runtime governance types).

[kostko]

add update_runtime runtime message support & e2e tests (maybe in a separate PR?).

Yes, this should be a separate PR.

[kostko]

Wouldn't it be better if we handled this in fixgenesis?

[abukosek]

No, because there are too many structures to duplicate and there's more chance of something going wrong with the conversion (and since this is in staking code it's better to be more careful). A two-line fix like this is cleaner, IMO :)
I'll file an issue later, so we don't forget to remove this once the upgrade is complete.

[abukosek]

Filed as #3627 :)

[abukosek]

Thanks for the comments! This is now ready for re-review.

[abukosek]

Thanks!