Security issue: insecure cryptography and dependencies

[paulmillr]

https://github.com/bitpay/bitcore/blob/f778e62c3bcaa6799f8be0bd870d7e3910d7e16f/packages/bitcore-lib/package.json#L43

has been long unmaintained; and had a few CVEs. I suggest doing following actions:

• replace elliptic with audited @noble/curves
• replace scryptsy with audited @noble/hashes
• upgrade ethers to v6, which stopped using elliptic
• remove bn.js, replace with native bigint

[kajoseph]

Thanks for the suggestions and concern. We're actively looking into and addressing this