Destination can be off-chain

[olanod]

A transfer destination will not always be an account within the blockchain, it can for example be a bank account or an account in a different blockchain that a liquidity provider controls and has notified the VLN of its existence.

This means to parameter of the Transfer call should change from an AccountId to an enum type that allows other types of off-chain destinations.
e.g.

enum Destination {
    Vln(AccountId),
    Bank(DetailsId),
    Btc(BtcId),
    // ...
}

[stanly-johnson]

@olanod This has been removed in the migration to v3. Is this no longer needed or should I work on integrating this back?

[olanod]

Hi Stan, it's still up for discussion but I didn't add it back since the new Multiaddress format might be just enough for representing external addresses and identifiers