clients/: add lab-exit to display an exit window with labnag.

closes #917
Summary follows:
- src/menu/menu.c: add `leave` action to call lab-exit.
- clients/meson.build: add install routine for lab-exit
and lab-sensible-terminal.
- meson.build remove lab-sensible-terminal routine re the comment.
- po/labwc.pot: rebuild with new xgettext commands.
- po/it.po: add translations for lab-exit and edit my email.
- CONTRIBUTING.md#translations: modify the instructions for coders as
two xgettext commands are needed since we now have two GUI facing
languages that have translatable strings.

po/it.po

@@ -1,7 +1,7 @@
 # Labwc pot file
 # Copyright (C) 2022
 # This file is distributed under the same license as the labwc package.
-# Mick Amadio <01micko@gmail.com>, 2022.
+# Mick Amadio <01micko@gmx.com>, 2022.
 #
 msgid ""
 msgstr ""
@@ -19,62 +19,66 @@ msgstr ""
 "Plural-Forms: nplurals=2; plural=n != 1;\n"
 "X-Generator: Weblate 4.2.1\n"
 
-#: src/menu/menu.c:1016
+#: src/menu/menu.c:867
+msgid "Always on Visible Workspace"
+msgstr ""
+
+#: src/menu/menu.c:924
 msgid "Go there..."
 msgstr "Vai lì..."
 
-#: src/menu/menu.c:1034
+#: src/menu/menu.c:943
 msgid "Terminal"
 msgstr "Terminale"
 
-#: src/menu/menu.c:1040
+#: src/menu/menu.c:949
 msgid "Reconfigure"
 msgstr "Riconfigura"
 
-#: src/menu/menu.c:1042
+#: src/menu/menu.c:951
 msgid "Exit"
 msgstr "Esci"
 
-#: src/menu/menu.c:1056
+#: src/menu/menu.c:966
 msgid "Minimize"
 msgstr "Minimizza"
 
-#: src/menu/menu.c:1058
+#: src/menu/menu.c:968
 msgid "Maximize"
 msgstr "Massimizza"
 
-#: src/menu/menu.c:1060
+#: src/menu/menu.c:970
 msgid "Fullscreen"
 msgstr "Schermo intero"
 
-#: src/menu/menu.c:1062
+#: src/menu/menu.c:972
 msgid "Roll Up/Down"
 msgstr "Arrotola/srotola"
 
-#: src/menu/menu.c:1064
+#: src/menu/menu.c:974
 msgid "Decorations"
 msgstr "Decorazioni"
 
-#: src/menu/menu.c:1066
+#: src/menu/menu.c:976
 msgid "Always on Top"
 msgstr "Sempre sopra"
 
-#: src/menu/menu.c:1071
-msgid "Move Left"
-msgstr "Sposta a sinistra"
-
-#: src/menu/menu.c:1078
-msgid "Move Right"
-msgstr "Sposta a destra"
-
-#: src/menu/menu.c:1083
-msgid "Always on Visible Workspace"
-msgstr "Sempre sull'area di lavoro visibile"
-
-#: src/menu/menu.c:1086
+#: src/menu/menu.c:980 src/menu/menu.c:999 src/config/rcxml.c:1708
 msgid "Workspace"
 msgstr "Area di lavoro"
 
-#: src/menu/menu.c:1089
+#: src/menu/menu.c:983
 msgid "Close"
 msgstr "Chiudi"
+
+#: clients/lab-exit:9
+msgid "Are you sure you want to quit Labwc?"
+msgstr "Sei sicuro di voler uscire da Labwc?"
+
+#: clients/lab-exit:10
+msgid "Yes"
+msgstr "Si"
+
+#: clients/lab-exit:11
+msgid "No"
+msgstr "No"