mox IMAP4rev2 service endpoint instance on returned bidirectional stream

[haraldrudell]

imaptemp.NewImapTemp runs temporary-storage mox imap-server listening on returned bidirectional stream for integration testing

#119 Ability to use mox over bidirectional stream: 2024: mox world’s only functional Go IMAP4rev2 server With few changes mox imapserver package can be used over a bidirectional socket io.ReadWriteCloser temporary or separate file-system storage configurable logging ability to disable timeouts enabling single-step debugging bypassing network stack integration-testing against mox IMAP service endpoint instance