Remove the “sales” box from the dashboard

There are no sales yet in Numerus, and having that summary there
confuses people.

He left the space there, without any text or background color, to
maintain the position of the rest.

Closes #87.

web/static/numerus.css

@@ -1040,10 +1040,6 @@ div[x-data="snackbar"] div[role="alert"].enter.end, div[x-data="snackbar"] div[r
     min-width: 33rem;
 }
 
-#income-statement div:first-child {
-    background-color: var(--numerus--color--yellow);
-}
-
 #income-statement div:nth-child(2) {
     background-color: var(--numerus--color--green);
 }

web/template/dashboard.gohtml

@@ -26,8 +26,6 @@
     </div>
     <dl id="income-statement">
         <div>
-            <dt>{{ (pgettext "Sales" "term") }}</dt>
-            <dd>{{ formatPriceSpan .Sales }}</dd>
         </div>
         <div>
             <dt>{{ (pgettext "Income" "term") }}</dt>