BIP-0039 support #4124
Description
Is your feature request related to a problem? Please describe.
I'm always frustrated when we don't support widely used standards.
Describe the solution you'd like
BIP-0039 is used by Neon/Metamask and many other wallets for generation/backup/restore, so many people now don't really know what WIF is, instead they know what words they have. They can have a trouble importing such keys into neo-go-managed NEP-6 wallet.
Describe alternatives you've considered
Not many, either we have it or not.
Additional context
neo-project/neo#4399
https://github.com/bitcoin/bips/blob/master/bip-0039.mediawiki