Don't borsh UnsignedSoftConfirmation to compute its hash

[kpp]

Description

Compute hash(UnsignedSoftConfirmation) on the fly without borshing it.

Fix: #1415

Also when we compute SignedSoftConfirmation the signature scheme is changed.

Before:

raw = borsh(UnsignedSoftConfirmation)
hash = Hash(raw) // sha256(raw)
signature = PrivateKey.sign(raw) // ed25519::sign( sha512(raw) )

After:

hash = Hash(UnsignedSoftConfirmation) // sha256(data)
signature = PrivateKey.sigh(hash) // ed25519::sign( sha512(hash) )

cc @ekrembal

[codecov]

Codecov Report

Attention: Patch coverage is 27.61905% with 76 lines in your changes missing coverage. Please review.

Project coverage is 76.6%. Comparing base (37aba6a) to head (e538b6d).
Report is 2 commits behind head on nightly.

Files with missing lines	Patch %	Lines
...module-system/sov-modules-stf-blueprint/src/lib.rs	28.5%	40 Missing ⚠️
crates/sequencer/src/runner.rs	31.0%	20 Missing ⚠️
...p-interface/src/state_machine/soft_confirmation.rs	20.0%	16 Missing ⚠️

Additional details and impacted files

Files with missing lines	Coverage Δ
crates/sovereign-sdk/rollup-interface/src/spec.rs	25.0% <ø> (ø)
...p-interface/src/state_machine/soft_confirmation.rs	82.2% <20.0%> (-10.3%)	⬇️
crates/sequencer/src/runner.rs	90.2% <31.0%> (-3.9%)	⬇️
...module-system/sov-modules-stf-blueprint/src/lib.rs	45.8% <28.5%> (-3.4%)	⬇️

... and 1 file with indirect coverage changes

[eyusufatik]

can we make this backward compatible with SpecId checks?
If not we cant merge

[kpp]

can we make this backward compatible with SpecId checks?

@eyusufatik #1437