String method for Voter

[wolf31o2]

Use CIP-105 and CIP-129 specifications to create the bech32 (string) representations of the Voter type in the ledger/common module. Prefer CIP-129 when possible.

An example of creating a bech32 string of and Address is here:

gouroboros/ledger/common/address.go

Line 416 in 582b32e

// String returns the bech32-encoded version of the address