Provide Run button in Editor Title Menu

This commit adds a editor title menu button for the
`powershell.Run` command which maps to the builtin VS Code Debug start
command. It places it in the primary navigation group, and
the uses `run` icon from the https://github.com/microsoft/vscode-icons
repo. This shows the button in the visible part of the menu when a
PowerShell file is open.

Author: jpogran

package.json

@@ -161,6 +161,15 @@
         },
         "category": "PowerShell"
       },
+      {
+        "command": "workbench.action.debug.start",
+        "title": "Run",
+        "category": "PowerShell",
+        "icon": {
+          "light": "resources/light/run.svg",
+          "dark": "resources/dark/run.svg"
+        }
+      },
       {
         "command": "PowerShell.RunSelection",
         "title": "Run Selection",
@@ -267,8 +276,13 @@
       "editor/title": [
         {
           "when": "resourceLangId == powershell",
-          "command": "PowerShell.RunSelection",
+          "command": "workbench.action.debug.start",
           "group": "navigation@100"
+        },
+        {
+          "when": "resourceLangId == powershell",
+          "command": "PowerShell.RunSelection",
+          "group": "navigation@101"
         }
       ],
       "editor/title/context": [