display reconciliation date on homepage

Summary: this patch adds the possibility to have the corrresponding reconciliation date displayed alongside each account on the home page. This is optional and can be enabled or disabled via a setting in the config dialog.

Reviewers: KMyMoney, tbaumgart, wojnilowicz

Reviewed By: KMyMoney, tbaumgart, wojnilowicz

Subscribers: wojnilowicz, ostroffjh, tbaumgart

Tags: KMyMoney

Differential Revision: https://phabricator.kde.org/D10001