Add current expenses to the overview

The period start is configurable.

financer-web-client/src/main/resources/templates/account/accountOverview.html

@@ -14,6 +14,10 @@
         <span th:text="#{financer.account-overview.status.current-assets}"/>
         <span th:text="${#numbers.formatDecimal(currentAssets/100D, 1, 'DEFAULT', 2, 'DEFAULT')}"/>
     </div>
+    <div th:title="#{'financer.account-overview.tooltip.status.current-expenses'(${periodStart}, ${periodEnd})}">
+        <span th:text="#{financer.account-overview.status.current-expenses}"/>
+        <span th:text="${#numbers.formatDecimal(currentExpenses/100D, 1, 'DEFAULT', 2, 'DEFAULT')}"/>
+    </div>
     <div>
         <span th:text="#{financer.account-overview.status.recurring-transaction-due-today}"/>
         <a th:href="@{/recurringTransactionDueToday}" th:text="${rtDueTodayCount}"/>