The invoicing information is present on the sponsorship dashboard,
but not on the detailed sponsorship view which can be confusing.
This adds the payment information on the detailed admin page.
<th>Status:</th>
<td>{%if sponsor.confirmed%}Confirmed ({{sponsor.confirmedat}}){%else%}<i>Awaiting confirmation (signed up {{sponsor.signupat}})</i>{%endif%}</td>
</tr>
+{%if sponsor.invoice%}
+ <tr>
+ <th>Payment status:</th>
+ <td>{%if sponsor.invoice.paidat%}Paid {{sponsor.invoice.paidat}}{%elif sponsor.invoice.isexpired%}Overdue{%else%}Invoiced{%endif%}</td>
+ </tr>
+{%endif%}
<tr>
<th>Edit:</th>
<td><a class="btn btn-default btn-sm" href="edit/">Edit sponsor</a></td>