tests(feature-activation): implement reorg test

[glevco]

Acceptance Criteria

• Add signal_bits to block templates
• Add signal_bits arg to miner simulator
• Change rule where an error would be raised if trying to retrieve a feature that is only defined in another network
• Add feature activation reorg test

Resolves #631

[codecov]

Codecov Report

Merging #660 (bfffecd) into master (6eaedc5) will increase coverage by 0.18%.
The diff coverage is 100.00%.

@@            Coverage Diff             @@
##           master     #660      +/-   ##
==========================================
+ Coverage   83.90%   84.08%   +0.18%     
==========================================
  Files         246      246              
  Lines       20390    20418      +28     
  Branches     2749     2754       +5     
==========================================
+ Hits        17108    17169      +61     
+ Misses       2709     2674      -35     
- Partials      573      575       +2     

Impacted Files	Coverage Δ
hathor/manager.py	77.21% <ø> (ø)
hathor/mining/block_template.py	88.46% <ø> (ø)
hathor/feature_activation/feature_service.py	97.22% <100.00%> (ø)
hathor/simulator/miner/geometric_miner.py	100.00% <100.00%> (ø)
hathor/transaction/block.py	92.24% <100.00%> (+0.46%)	⬆️
hathor/transaction/transaction_metadata.py	91.12% <100.00%> (+0.44%)	⬆️

... and 7 files with indirect coverage changes

The base branch was changed.