Use Ed25519 curve instead of BLS signatures for transaction verification in validator nodes

[ibitec7]

Issue:
Current implementation of BLS signatures for transaction verification is significantly slower than its alternatives. BLS signatures is best used for aggregate signatures where it may outperform its alternatives such as the case for signing an entire block.

Solution:
Use the newer Ed25519 curve for digital signature signing and verification. This algorithm is significantly faster than the BLS signatures and may lead to enhanced transaction throughput for the validators while offering similar security.

Alternatives Considered:
ECDSA is also a high performing algorithm but it is not as performant in terms of verification as the Ed25519 curve. The ECDSA is best for key-exchanges while it still is better performing than the BLS algorithm.

Additional Context:
The current transaction throughput is already significantly slower than the block throughput. Using the Ed25519 curve may significantly improve performance especially protect against DDoS attacks where quickly rejecting fraudulent transactions is crucial.

Read more at: https://eprint.iacr.org/2021/377.pdf