The operator-generated TSIG Secret previously carried only the managed-by
label, so it could not be mirrored to another namespace by emberstack
reflector (which requires reflection-allowed annotations on the source).
Add spec.secretTemplate.{annotations,labels}, applied both when the Secret
is first generated and reconciled onto the existing Secret when the CR
changes (imported secrets are left untouched so we don't fight their
external manager). This lets the external-dns TSIG key be managed in
bind-internal and reflected into the externaldns namespace.
unkinben