Customer-admin Mail settings backed by Stalwart JMAP: per-tenant aliases
(extra addresses routing to a mailbox) and distribution lists (one address
fanning out to many recipients). Adds StalwartClient x:Alias/x:MailingList
methods, a tenant-scoped MailController/MailService, the portal Mail settings
page and its proxy routes, and the mailboxAddress field on TenantUserDoc.
Removes the old mock mail data now that the page reads live data.
Ronni Baslund
aee8f13899