UI: Add pick-configuration command to the main menu

In addition to the bottom right selector, make it available through
the view's menu and context menus. The active config is now displayed
on the view's title, so it's better to have a selector in that UI area.

package.json

@@ -386,7 +386,7 @@
       },
       {
         "command": "bitbake.pick-configuration",
-        "title": "BitBake: Pick configuration",
+        "title": "BitBake: Change active buildConfiguration",
         "description": "Select the active build configuration from the settings to use for bitbake commands."
       },
       {
@@ -622,6 +622,10 @@
           "command": "bitbake.examine-dependency-taskexp",
           "group": "1@bitbake_dev@5"
         },
+        {
+          "command": "bitbake.pick-configuration",
+          "group": "1@bitbake_dev@6"
+        },
         {
           "command": "bitbake.devtool-modify",
           "group": "2@bitbake_devtool@0"