Allow an issuer to whitelist (in a single transaction) all KYC verified customers for a given KYC provider

[adamdossa]

This would allow an issuer to avoid the somewhat painful process of individually (or in batches) adding investors to a security tokens whitelist. It would mean the issuer would need to fully trust the KYC provider to maintain the whitelist on their behalf going forward, but this would be optional (i.e. the current behaviour of explicitely adding investors to the whitelist would remain, this would be another option).