Added upstream tests to azure pipelines

* Moved azure CI definitions from azure-pipelines.yml to
  tests/azure/azure-pipelines.yml.
* Updated azure CI definitions to run playbook tests using docker
  containers.

tests/azure/azure-pipelines.yml

@@ -0,0 +1,43 @@
+trigger:
+- master
+
+pool:
+  vmImage: 'ubuntu-18.04'
+
+jobs:
+- job: RunLinters
+  displayName: Run Linters
+  steps:
+  - task: UsePythonVersion@0
+    inputs:
+      versionSpec: '3.6'
+
+  - script: python -m pip install --upgrade pip setuptools wheel
+    displayName: Install tools
+
+  - script: pip install pydocstyle flake8
+    displayName: Install dependencies
+
+  - script: flake8 .
+    displayName: Run flake8 checks
+
+  - script: pydocstyle .
+    displayName: Verify docstings
+
+- template: templates/playbook_tests.yml
+  parameters:
+    group_number: 1
+    number_of_groups: 3
+    build_number: $(Build.BuildNumber)
+
+- template: templates/playbook_tests.yml
+  parameters:
+    group_number: 2
+    number_of_groups: 3
+    build_number: $(Build.BuildNumber)
+
+- template: templates/playbook_tests.yml
+  parameters:
+    group_number: 3
+    number_of_groups: 3
+    build_number: $(Build.BuildNumber)