Add icons and enable setting for Command Explorer (#1638)

* Add icons for Command Explorer
Change refrech icon to use octicons (https://octicons.github.com)

* Update Command Palette
Reword Refresh to specify what it's Refreshing.
Remove Insert from Command Palette.

* Add Configuration to toggle Command Explorer visibility.

* sidebar -> Side Bar
Be consistent with UI

Author: corbob

package.json

@@ -72,7 +72,8 @@
       "PowerShellCommandExplorer": [
         {
           "id": "PowerShellCommands",
-          "name": "PowerShell Commands"
+          "name": "PowerShell Commands",
+          "when": "config.powershell.sideBar.CommandExplorerVisibility"
         }
       ]
     },
@@ -113,16 +114,20 @@
       },
       {
         "command": "PowerShell.RefreshCommandsExplorer",
-        "title": "Refresh",
+        "title": "Refresh Command Explorer",
         "icon": {
-          "light": "resources/light/refresh.svg",
-          "dark": "resources/dark/refresh.svg"
+          "light": "resources/light/sync.svg",
+          "dark": "resources/dark/sync.svg"
         },
         "category": "PowerShell"
       },
       {
         "command": "PowerShell.InsertCommand",
         "title": "Insert Command",
+        "icon": {
+          "light": "resources/light/pencil.svg",
+          "dark": "resources/dark/pencil.svg"
+        },
         "category": "PowerShell"
       },
       {
@@ -133,6 +138,10 @@
       {
         "command": "PowerShell.ShowHelp",
         "title": "Get Help for Command",
+        "icon": {
+          "light": "resources/light/question.svg",
+          "dark": "resources/dark/question.svg"
+        },
         "category": "PowerShell"
       },
       {
@@ -202,6 +211,16 @@
       }
     ],
     "menus": {
+      "commandPalette": [
+        {
+          "command": "PowerShell.InsertCommand",
+          "when": "false"
+        },
+        {
+          "command": "PowerShell.RefreshCommandsExplorer",
+          "when": "config.powershell.sideBar.CommandExplorerVisibility"
+        }
+      ],
       "editor/context": [
         {
           "when": "editorLangId == powershell",
@@ -224,11 +243,13 @@
       "view/item/context": [
         {
           "command": "PowerShell.ShowHelp",
-          "when": "view == PowerShellCommands"
+          "when": "view == PowerShellCommands",
+          "group": "inline@1"
         },
         {
           "command": "PowerShell.InsertCommand",
-          "when": "view == PowerShellCommands"
+          "when": "view == PowerShellCommands",
+          "group": "inline@2"
         }
       ]
     },
@@ -456,6 +477,11 @@
       "type": "object",
       "title": "PowerShell Configuration",
       "properties": {
+        "powershell.sideBar.CommandExplorerVisibility": {
+          "type": "boolean",
+          "default":true,
+          "description": "Specifies the visibility of the Command Explorer in the PowerShell Side Bar."
+        },
         "powershell.powerShellExePath": {
           "type": "string",
           "default": "",