ci: remove unused containers

Author: deepak1556

centos7-devtoolset8-arm64/Dockerfile renamed to archived/centos7-devtoolset8-arm64/Dockerfile_Unused

@@ -152,25 +152,6 @@ stages:
       #        arch: snapcraft-x64
       #        release: ${{ parameters.dockerhub_release }}
 
-      - job: centos_x64
-        pool:
-          vmImage: 'ubuntu-latest'
-        steps:
-          - template: build-containers.yml
-            parameters:
-              arch: centos7-devtoolset8-x64
-              release: ${{ parameters.dockerhub_release }}
-
-      - job: centos_arm64
-        pool:
-          vmImage: 'ubuntu-latest'
-        steps:
-          - template: build-containers.yml
-            parameters:
-              arch: centos7-devtoolset8-arm64
-              qemu: 'true'
-              release: ${{ parameters.dockerhub_release }}
-
       - job: bionic_armhf
         pool:
           vmImage: 'ubuntu-latest'