feat(feature-activation): implement bit signaling sysctl

[glevco]

Motivation

Add sysctl commands to control Feature Activation bit signaling without having to restart the full node (previously, this was only available through CLI options). The commands are the following:

core.features.supported_features

Return features that are explicitly enabled. Read-only.

core.features.not_supported_features

Return features that are explicitly disabled. Read-only.

core.features.signaling_features

Return which feature are currently in a signaling phase. Read-only.

core.features.add_support

Add support for a feature. Write-only.

core.features.remove_support

Remove support for a feature. Write-only.

Example

$ nc -U /tmp/hathor.sock
core.features.signaling_features
["NOP_FEATURE_5"]
core.features.remove_support="NOP_FEATURE_5"
core.features.not_supported_features
["NOP_FEATURE_5"]
core.features.supported_features
[]
core.features.add_support="NOP_FEATURE_5"
core.features.not_support_features
[]
core.features.supported_features
["NOP_FEATURE_5"]

Then, the bits in the block template will be changed accordingly.

Acceptance Criteria

• Add core.features sysctl command group with the following subcommands: supported_features, not_supported_features, signaling_features, add_support, and remove_support.

Checklist

• If you are requesting a merge into master, confirm this code is production-ready and can be included in future releases as soon as it gets merged

[codecov]

Codecov Report

Attention: Patch coverage is 73.68421% with 15 lines in your changes are missing coverage. Please review.

Project coverage is 85.04%. Comparing base (881c5ff) to head (4b44a2a).

Files	Patch %	Lines
hathor/feature_activation/bit_signaling_service.py	53.84%	12 Missing ⚠️
hathor/builder/sysctl_builder.py	25.00%	3 Missing ⚠️

Additional details and impacted files

@@             Coverage Diff             @@
##           master     #962       +/-   ##
===========================================
+ Coverage        0   85.04%   +85.04%     
===========================================
  Files           0      296      +296     
  Lines           0    22918    +22918     
  Branches        0     3451     +3451     
===========================================
+ Hits            0    19490    +19490     
- Misses          0     2741     +2741     
- Partials        0      687      +687     

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