Add config param that displays the whole git graph by default

docs/Config.md

@@ -75,6 +75,8 @@ git:
     # one of always, never, when-maximised
     # this determines whether the git graph is rendered in the commits panel
     showGraph: 'when-maximised'
+    # displays the whole git graph by default in the commits panel
+    showWholeGraph: false
   skipHookPrefix: WIP
   autoFetch: true
   autoRefresh: true