Migrate DIP3 Masternodes to New BLS Scheme

[LexxXell]

Migrate DIP3 Masternodes to New BLS Scheme

This pull request introduces support for payload version 2 in the ProUpServTx implementation, marking a significant migration of masternodes to the new BLS key scheme.

Key Changes:

1. Support for ProTx Payload Version 2:

   • Implemented logic to handle serialization and signing for version 2 using the BasicSchemeMPL approach.
   • Maintained backward compatibility with version 1 to ensure a smooth transition for existing masternodes.

2. Code Review and Updates:

   • The previous implementation was partially functional; some features worked as expected, while others did not.
   • Reviewed and updated the codebase to address inconsistencies and ensure robust support for the new key scheme.
   • Addressed issues related to legacy masternodes running on the older version.

3. Breaking Changes:

   • Masternodes now operate using a new key format in compliance with the updated BLS scheme.
   • This migration renders the previous key format obsolete, requiring node operators to update accordingly.

4. Validation Enhancements:

   • Added checks to gracefully handle unsupported payload versions, improving the reliability of the system.

5. Thorough Testing:

   • Verified compatibility and consistency across both version 1 and version 2 payloads.
   • Comprehensive testing ensures the reliability of the migration process.

Notes:

• This update resolves Issue Error sending BIP3 Update Service transaction #27.