parachain bitfield signer

[turuslan]

Referenced issues

• Data availability #1311

Description of the Change

Fix BitVec.
Add bitfield store.
Add bitfield signer.

Benefits

• Store signed bitfields.
• Sign bitfield for new heads.
• Reusable ValidatorSigner.
• Interface will be used by multiple components (bitfield signing, approval, ...).

Possible Drawbacks

• Implement pruning later.
• TODO: broadcast bitfield.
• TODO: call BitfieldSigner::start somewhere in injector.

Usage Examples or Tests

Alternate Designs

[codecov]

Codecov Report

Merging #1336 (af994b1) into master (3834e5a) will decrease coverage by 0.10%.
The diff coverage is 0.00%.

@@            Coverage Diff             @@
##           master    #1336      +/-   ##
==========================================
- Coverage   24.50%   24.40%   -0.11%     
==========================================
  Files         612      619       +7     
  Lines       22984    23080      +96     
  Branches    11998    12045      +47     
==========================================
  Hits         5633     5633              
- Misses      12149    12245      +96     
  Partials     5202     5202              

Impacted Files	Coverage Δ
...e/consensus/babe/impl/parachains_inherent_data.hpp	6.41% <ø> (+0.59%)	⬆️
core/crypto/crypto_store/session_keys.cpp	29.16% <0.00%> (-12.01%)	⬇️
core/injector/application_injector.cpp	32.12% <ø> (ø)
core/parachain/availability/bitfield/signer.cpp	0.00% <0.00%> (ø)
core/parachain/availability/bitfield/store.hpp	0.00% <0.00%> (ø)
...ore/parachain/availability/bitfield/store_impl.cpp	0.00% <0.00%> (ø)
...ore/parachain/availability/bitfield/store_impl.hpp	0.00% <0.00%> (ø)
core/parachain/availability/store/store.hpp	0.00% <0.00%> (ø)
core/parachain/validator/signer.cpp	0.00% <0.00%> (ø)
core/parachain/validator/signer.hpp	0.00% <0.00%> (ø)

📣 We’re building smart automated test selection to slash your CI/CD build times. Learn more