Confine contact addresses to the WFE

[aarongable]

Change the WFE to stop populating the Contact field of the NewRegistration requests it sends to the RA. Similarly change the WFE to ignore the Contact field of any update-account requests it receives, thereby removing all calls to the RA's UpdateRegistrationContact method.

Hoist the RA's contact validation logic into the WFE, so that we can still return errors to clients which are presenting grossly malformed contact fields, and have a first layer of protection against trying to send malformed addresses to email-exporter.

A follow-up change (after a deploy cycle) will remove the deprecated RA and SA methods.

Part of #8199

[jsha]

Note that this does mean that we're no longer performing any validation of contact addresses, since that happened in the RA. But that's fine, because we're not storing them anymore, either.

Aren't we sending them to the email exporter? It would be nice to retain the validation we have, and continue failing registration and not sending them to the exporter.

[aarongable]

It would be nice to retain the validation we have, and continue failing registration and not sending them to the exporter.

That's a good point; I was forgetting that we only send contacts to email-exporter after account creation has succeeded, and that therefore we were implicitly still validating the addresses before exporting them. I've hoisted this validation into the WFE directly now.

[beautifulentropy]

Overall the change looks great. I especially like that you moved the validation up near the top of NewAccount.

[github-actions]

@aarongable, this PR appears to contain configuration and/or SQL schema changes. Please ensure that a corresponding deployment ticket has been filed with the new values.