outline has been added to choose columns links (#1454)

* arialabel has been added to close button of invitational youtube video

* heading role has been addedd and tag has been changed to h1

* outline has been restored to choose columns link in entities page

* Update QuickstartCarousel.tsx

* Update SplashScreen.tsx

* Update TableEntity.tsx

* outline for edit entity has been added on focus

src/Common/TableEntity.tsx

@@ -137,7 +137,7 @@ export const TableEntity: FunctionComponent<TableEntityProps> = ({
         />
         {!isEntityValueDisable && (
           <TooltipHost content="Edit property" id="editTooltip">
-            <div tabIndex={0}>
+            <div>
               <Image
                 {...imageProps}
                 src={EditIcon}