Create tabs manager and refactor tab related logic (#66)

Co-authored-by: Steve Faulkner <southpolesteve@gmail.com>

src/Explorer/Tabs/TabComponents.ts

@@ -16,6 +16,7 @@ import TriggerTabTemplate from "./TriggerTab.html";
 import UserDefinedFunctionTabTemplate from "./UserDefinedFunctionTab.html";
 import GalleryTabTemplate from "./GalleryTab.html";
 import NotebookViewerTabTemplate from "./NotebookViewerTab.html";
+import TabsManagerTemplate from "./TabsManager.html";
 
 export class TabComponent {
   constructor(data: any) {
@@ -23,6 +24,15 @@ export class TabComponent {
   }
 }
 
+export class TabsManager {
+  constructor() {
+    return {
+      viewModel: TabComponent,
+      template: TabsManagerTemplate
+    };
+  }
+}
+
 export class DocumentsTab {
   constructor() {
     return {