Switch queue name for dnceng and rename yaml files directory (#1481)

Update queue names to to work on https://dev.azure.com/dnceng. Also, react to VSTS => Azure DevOps rebranding.

.azure/pipelines/ci-official.yml

@@ -5,7 +5,7 @@ trigger:
 phases:
 - template: ../templates/blazor-build.yml
   parameters:
-    queueName: VSEng-MicroBuildVS2017
+    queueName: DotNetCore-Windows
     variables:
       SignType: real
       TeamName: AspNetCore
@@ -14,13 +14,13 @@ phases:
       displayName: 'Run compliance check'
       inputs:
         targetType: F
-    - task: ms-vseng.MicroBuildTasks.30666190-6959-11e5-9f96-f56098202fef.MicroBuildSigningPlugin@1
+    - task: MicroBuildSigningPlugin@1
       displayName: Install CodeSigning plugin
       inputs:
         signType: $(SignType)
       condition: and(succeeded(), in(variables['SignType'], 'test', 'real'))
 
     afterBuild:
-    - task: ms-vseng.MicroBuildTasks.521a94ea-9e68-468a-8167-6dcf361ea776.MicroBuildCleanup@1
+    - task: MicroBuildCleanup@1
       displayName: Perform Cleanup Tasks
       condition: succeededOrFailed()