Added Azure pipelines to build test containers

Added a pipeline file (tests/azure/build-containers.yml) to build test
containers and upload them to quay.io. The pipeline will create
containers with IPA pre-installed for testing proposes on three
different Linux containers: CentOS 7, CentOS 8 and Fedora Latest.

tests/azure/build-containers.yml

@@ -0,0 +1,31 @@
+---
+
+schedules:
+- cron: "0 0 * * *"
+  displayName: Daily midnight build
+  branches:
+    include:
+    - master
+
+pool:
+  vmImage: 'ubuntu-18.04'
+
+jobs:
+
+- template: templates/build_container.yml
+  parameters:
+    job_name_suffix: Centos7
+    container_name: centos-7
+    build_scenario_name: centos-7-build
+
+- template: templates/build_container.yml
+  parameters:
+    job_name_suffix: Centos8
+    container_name: centos-8
+    build_scenario_name: centos-8-build
+
+- template: templates/build_container.yml
+  parameters:
+    job_name_suffix: FedoraLatest
+    container_name: fedora-latest
+    build_scenario_name: fedora-latest-build