Introduce VBytes factor for block issuer keys and staking.

[piotrm50]

Description of change

Introduce VBytes factor for block issuer keys and staking.

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• Bug fix (a non-breaking change which fixes an issue)
• Enhancement (a non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to not work as expected)
• Documentation Fix

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Change checklist

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• My code follows the contribution guidelines for this project
• I have performed a self-review of my own code
• I have commented my code, particularly in hard-to-understand areas
• I have made corresponding changes to the documentation
• I have added tests using ginkgo that prove my fix is effective or that my feature works
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[alexsporn]

we should remove this constants because they should always come from the protocol parameters

[piotrm50]

Done.