Merge upstream/master: translation wave plus generic device

Upstream moved 56 commits ahead of the last merge. Six files conflicted,
all of them files where upstream's French -> English tr() translation wave
touched lines we had also touched with the cable feature. Resolution rule
applied everywhere: take upstream's English source strings, keep our cable
additions.

Resolved:

- sources/ui/xrefpropertieswidget.ui : kept our structure (m_labels_gb
  pulled out of the display group, m_slave_row, the m_font_pb "Police..."
  button of the cable cross-reference) and mechanically applied upstream's
  20 English string replacements on top of it.

- sources/ui/xrefpropertieswidget.cpp : our version plus upstream's 7
  translated combo entries; the tr("Cable") item we add for the cable
  cross-reference type stays.

- sources/autoNum/ui/numparteditorw.cpp : upstream's English part names
  ("number format 1", "Sheet no.", "Plant", "Location", ...) for the
  number-format list, with our comment explaining why type 3 (cable) takes
  the conductor kinds of variable.

- sources/ui/configpage/configpages.cpp : upstream's English tab titles
  (Conductors / Elements / Sheets) plus our Cables tab.

- sources/ui/configpage/projectconfigpages.cpp : upstream's "Sheets" tab
  title plus our Cables tab block (single-rule SelectAutonumW(3)).

- sources/qetdiagrameditor.cpp : union of both sides - upstream's new
  "Add a generic device" action (icon, status tip, data id) and its
  English menu names ("File"/"Edit"/"Project"/"Display"), together with our
  cable action, the Numbering and Lists menus, the cable list actions and
  the CSV export in the Project menu.

Kept French: our own cable tr() source strings stay French for now. That
is the smaller change and the translation pass can follow separately.

Verified: full build 1065/1065, ctest 91/92 (only the pre-existing
headless tst_menubarkeyboard fails: no window manager, so Alt+F and F10
cannot open a menu bar), smoke start exit 124, no conflict marker left in
the tree.

sources/elementsmover.cpp

@@ -98,8 +98,8 @@ int ElementsMover::beginMovement(Diagram *diagram, QGraphicsItem *driver_item)
 			&& !m_moved_content.items().contains(driver_item);
 	if (m_driver_held && m_status_bar) {
 		m_status_bar->showMessage(QObject::tr(
-			"Ce groupe ne peut pas être déplacé : "
-			"la position d'un de ses éléments est verrouillée."));
+			"This group cannot be moved: the position of one "
+			"of its elements is locked."));
 	}
 
 		//Remove element text and text group, if the parent element is selected.
@@ -329,7 +329,7 @@ void ElementsMover::endMovement()
 					//Create an undo object for each new auto conductor, with undo_object for parent
 				new AddGraphicsObjectCommand(conductor, m_diagram, QPointF(), undo_object);
 				if (undo_object->text().isEmpty())
-					undo_object->setText(QObject::tr("Ajouter %n conducteur(s)", "add a numbers of conductor one or more", acc));
+					undo_object->setText(QObject::tr("Add %n conductors", "add a numbers of conductor one or more", acc));
 
 					//Get all conductors at the same potential of conductor
 				const auto conductors_list{conductor->relatedPotentialConductors()};