Dataexplorer viewlet (#3967)

* added initial data explorer viewlet

* added dataexplorer contribution point

* removed test view

* remove unused imports

* added flag and tests

* CR comments

* added icon for data explorer

extensions/azurecore/package.json

@@ -122,6 +122,14 @@
 				}
 			]
 		},
+		"dataExplorer": {
+			"azureResource": [
+				{
+					"id": "azureResourceExplorer",
+					"name": "%azure.resource.explorer.title%"
+				}
+			]
+		},
 		"menus": {
 			"view/title": [
 				{