Merge bitcoin-core/gui#543: peers-tab: add connection duration column to tableview

51708c4516 gui: peersWidget - ResizeToContents Age and IP/Netmask columns (randymcmillan)
209301a442 gui: add Age column to peers tab (randymcmillan)
127de22c5f gui: add FormatPeerAge() utility helper (Jon Atack)

Pull request description:

  This change adds an "Age" column to the peers table view,
  which displays the duration of each peer's connection.

ACKs for top commit:
  jonatack:
    re-ACK  51708c4516
  Jamewood:
    > re-ACK 51708c4
  shaavan:
    reACK 51708c4516
  hebasto:
    ACK 51708c4516, I have reviewed the code and it looks OK, I agree it can be merged.

Tree-SHA512: 27323f7080ec0d3fcdbf1b190fba1cd2d7406840ab6607c221cf8af950db9134e22721cc5a88f4fc4f390d8b05e98bc4b7521661a31fadad9e2c6c6390e71788

src/qt/peertablemodel.cpp

@@ -71,6 +71,8 @@ QVariant PeerTableModel::data(const QModelIndex& index, int role) const
         switch (column) {
         case NetNodeId:
             return (qint64)rec->nodeStats.nodeid;
+        case Age:
+            return GUIUtil::FormatPeerAge(rec->nodeStats.m_connected);
         case Address:
             return QString::fromStdString(rec->nodeStats.m_addr_name);
         case Direction:
@@ -96,6 +98,7 @@ QVariant PeerTableModel::data(const QModelIndex& index, int role) const
     } else if (role == Qt::TextAlignmentRole) {
         switch (column) {
         case NetNodeId:
+        case Age:
             return QVariant(Qt::AlignRight | Qt::AlignVCenter);
         case Address:
             return {};