Doc: Add a summary of Navigator icons and the actions they apply

Change the topic name to Navigator and move the topic under
Design views in the TOC.

Replace occurrences of "item" and "QML type" with "component".

Task-number: QDS-3771
Change-Id: I7dbe9803d88a409c8ba0a0ef074e2bc8a6866dec
Reviewed-by: Leena Miettinen <riitta-leena.miettinen@qt.io>

doc/qtcreator/src/qtquick/qtquick-component-context-menu.qdocinc

@@ -37,10 +37,10 @@
         \li Go To
     \row
         \li Arrange
-        \li \l{Arranging Items}
+        \li \l{Arranging Components}
     \row
         \li Edit
-        \li \l{Showing and Hiding Items}
+        \li \l{Showing and Hiding Components}
     \row
         \li Anchors
         \li \l{Setting Anchors and Margins}